Centering Text in Table Cell

Question

I have tried to center text within a cell in my table by defining a new column type = \newcolumntype{C}[1]{>{\centering\arraybackslash}m{#1}}

Yet in my MWE, my contents are still not centering

MWE:

\documentclass{article}

\usepackage{multirow}
\usepackage{multicol}
\usepackage{array}

\newcounter{vonecount}
\setcounter{vonecount}{0}
\newcommand{\vone}{\stepcounter{vonecount}\thevonecount}

\newcolumntype{C}[1]{>{\centering\arraybackslash}m{#1}}

\begin{document}

\begin{tabular}{r|C{2mm}|C{2mm}|C{2mm}|C{2mm}|C{2mm}|C{2mm}|C{2mm}|C{2mm}|C{2mm}|C{2mm}|C{2mm}|C{2mm}|C{2mm}|C{2mm}|C{2mm}|C{2mm}|C{2mm}|C{2mm}} 
\cline{1-18}
\multicolumn{1}{|r|}{Section One}                           &   
\multicolumn{17}{>{\centering}p{4in}|}{Part One - Synonyms} \\ 
\cline{1-18}
Question \#     &   
\vone & 
\vone & 
\vone & 
\vone & 
\vone & 
\vone & 
\vone & 
\vone & 
\vone & 
\vone & 
\vone & 
\vone & 
\vone & 
\vone & 
\vone & 
\vone & 
\vone \\
\cline{2-18}
Correct Answer  & 
A & 
A & 
A & 
A & 
A & 
A & 
A & 
A & 
A & 
A & 
A & 
A & 
A & 
A & 
A & 
A & 
A \\
Your Answer     & & & & & & & & & & & & & & & & & &  \\
\cline{1-18}
\multicolumn{1}{|r|}{Section One}                                       &   
\multicolumn{17}{>{\centering}p{4in}|}{Part Two - Sentence Completions} \\ 
\cline{1-18}
Question \#     &   
\vone & 
\vone & 
\vone & 
\vone & 
\vone & 
\vone & 
\vone & 
\vone & 
\vone & 
\vone & 
\vone & 
\vone & 
\vone & 
\vone & 
\vone & 
\vone & 
\vone \\
\cline{2-18}
Correct Answer  &   
A & 
A & 
A & 
A & 
A & 
A & 
A & 
A & 
A & 
A & 
A & 
A & 
A & 
A & 
A & 
A & 
A \\
Your Answer     & & & & & & & & & & & & & & & & & &  \\
\hline
\multirow{2}{*}{Scores}                 &   
\multicolumn{4}{c|}{Correct}            &   
\multicolumn{4}{c|}{Total}              &   
\multicolumn{4}{c|}{Stanine}            &   
\multicolumn{5}{c|}{Percentile Rank}    \\
\cline{2-18}
                        &   
\multicolumn{4}{c|}{}   &   
\multicolumn{4}{c|}{}   &   
\multicolumn{4}{c|}{}   &   
\multicolumn{5}{c|}{}   \\
\cline{2-18}
\end{tabular}

\end{document}

Answer 1

You can obtain what you want with the tabularx package:

\documentclass{article}

\usepackage[utf8]{inputenc}
\usepackage{geometry}
\usepackage{multirow}
\usepackage{array, colortbl, tabularx}

\newcommand\redhline{\arrayrulecolor{red}\hline\arrayrulecolor{black}}
\newcommand\vredrule{\color{red}\vrule}
\newcounter{vonecount}
\setcounter{vonecount}{0}
\newcommand{\vone}{\stepcounter{vonecount}\thevonecount}

\newcolumntype{C}[1]{>{\centering\arraybackslash}X}

\usepackage{makecell}
\setcellgapes{5pt}
\makegapedcells

\begin{document}

Text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text. \\
%
%\begin{center}
%\setlength\tabcolsep{5pt}
%\begin{tabular}{r|*{17}{c|}}
%\redhline
%\multicolumn{1}{!{\vredrule}r!{\vredrule}}{Section One} &
%\multicolumn{17}{c!{\vredrule}}{Part One -- Synonyms} \\
%\redhline
%Question \# &
%\vone & \vone & \vone & \vone & \vone & \vone & \vone & \vone & \vone
%& \vone & \vone & \vone & \vone & \vone & \vone & \vone & \vone \\
%\cline{2-18}
%Correct Answer &
%A & A &A & A & A & A & A & A & A &
%A & A & A & A & A & A & A & A \\
%Your Answer & & & & & & & & & & & & & & & & & \\
%\redhline
%\multicolumn{1}{!{\vredrule}r!{\vredrule}}{Section One} &
%\multicolumn{17}{c!{\vredrule}}{Part Two -- Sentence Completions} \\
%\arrayrulecolor{red}\hline\arrayrulecolor{black}
%Question \# &
%\vone & \vone & \vone & \vone & \vone & \vone & \vone & \vone & \vone
%& \vone & \vone & \vone & \vone & \vone & \vone & \vone & \vone \\
%\cline{2-18}
%Correct Answer &
%A & A & A & A & A & A & A & A & A &
%A & A & A & A & A & A & A & A \\
%Your Answer & & & & & & & & & & & & & & & & & \\
%\redhline
%\multicolumn{1}{!{\vredrule}r!{\vredrule}}{\multirow{2}{*}{Scores}}&
%\multicolumn{4}{c|}{Correct} &
%\multicolumn{4}{c|}{Total} &
%\multicolumn{4}{c|}{Stanine} &
%\multicolumn{5}{c!{\vredrule}}{Percentile Rank} \\
%\cline{2-18}
%\multicolumn{1}{!{\vredrule}r!{\vredrule}}{}&
%\multicolumn{4}{c|}{} & \multicolumn{4}{c|}{} & \multicolumn{4}{c|}{} & \multicolumn{5}{c!{\vredrule}}{} \\
%\redhline
%\end{tabular}
%\end{center}

\noindent
\begin{tabularx}{\linewidth}{r|*{17}{X|}}
\redhline
\multicolumn{1}{!{\vredrule}r!{\vredrule}}{Section One} &
\multicolumn{17}{c!{\vredrule}}{Part One -- Synonyms} \\
\redhline
Question \# &
\vone & \vone & \vone & \vone & \vone & \vone & \vone & \vone & \vone
& \vone & \vone & \vone & \vone & \vone & \vone & \vone & \vone \\
\cline{2-18}
Correct Answer &
A & A &A & A & A & A & A & A & A &
A & A & A & A & A & A & A & A \\
Your Answer & & & & & & & & & & & & & & & & & \\
\redhline
\multicolumn{1}{!{\vredrule}r!{\vredrule}}{Section One} &
\multicolumn{17}{c!{\vredrule}}{Part Two -- Sentence Completions} \\
\arrayrulecolor{red}\hline\arrayrulecolor{black}
Question \# &
\vone & \vone & \vone & \vone & \vone & \vone & \vone & \vone & \vone
& \vone & \vone & \vone & \vone & \vone & \vone & \vone & \vone \\
\cline{2-18}
Correct Answer &
A & A & A & A & A & A & A & A & A &
A & A & A & A & A & A & A & A \\
Your Answer & & & & & & & & & & & & & & & & & \\
\redhline
\multicolumn{1}{!{\vredrule}r!{\vredrule}}{\multirow{2}{*}{Scores}}&
\multicolumn{4}{c|}{Correct} &
\multicolumn{4}{c|}{Total} &
\multicolumn{4}{c|}{Stanine} &
\multicolumn{5}{c!{\vredrule}}{Percentile Rank} \\
\cline{2-18}
\multicolumn{1}{!{\vredrule}r!{\vredrule}}{}&
\multicolumn{4}{c|}{} & \multicolumn{4}{c|}{} & \multicolumn{4}{c|}{} & \multicolumn{5}{c!{\vredrule}}{} \\
\redhline
\end{tabularx}
\end{document}