Illegal pream-token in tabular

I'm having trouble constructing a tabular environment and compiling it with pdflatex. Here's what I'm trying to do:

\documentclass{article}
\usepackage[pdftex]{graphicx}
\usepackage{caption,tabularx,booktabs}
\begin{document}
\begin{minipage}{\linewidth}
\centering
\captionof{table}{Left side FBD} \label{tab:title2}
\begin{tabular}{ C C }\toprule[1.5pt]
\bf X & \b
f Y \\\midrule
$0$ & $-F_g$\\
$F_t \sin \theta$ & $F_t \cos \theta$\\
$-F_e$ & $0$\\
\bottomrule[1.25pt]
$0$ & $0$\\
\end{tabular}
\end{minipage}
\end{document}


However, I then get the following error:

! Package array Error:  Illegal pream-token (C): c' used.

See the array package documentation for explanation.
Type  H <return>  for immediate help.
...

l.8 \begin{tabular}{ C C }
\toprule[1.5pt]

! Package array Error:  Illegal pream-token (C): c' used.


I've tried giving each C and argument as I've seen in other source code (I'm still not certain exactly what that argument is for) I get another error message. When I replace C with C{.85in} I now get:

! Package array Error:  Illegal pream-token (C): c' used.

See the array package documentation for explanation.
Type  H <return>  for immediate help.
...

l.8 \begin{tabular}{ C{.85in} C{.85in} }
\toprule[1.5pt]

! Package array Error:  Illegal pream-token (.85in): c' used.


Does anyone know what I'm doing wrong with my tabular? Thanks in advance!

-
Welcome to TeX.sx! – Marco Daniel Apr 23 '13 at 18:59
Use a small c instead of C: \begin{tabular}{ c c } – Marco Daniel Apr 23 '13 at 18:59

here is the fixed MWE:

\documentclass{article}
\usepackage[pdftex]{graphicx}
\usepackage{caption,tabularx,booktabs}
\begin{document}
\begin{minipage}{\linewidth}
\centering
\captionof{table}{Left side FBD} \label{tab:title2}
\begin{tabular}{ c c }\toprule[1.5pt]
\bf X & \b
f Y \\\midrule
$0$ & $-F_g$\\
$F_t \sin \theta$ & $F_t \cos \theta$\\
$-F_e$ & $0$\\
\bottomrule[1.25pt]
$0$ & $0$\\
\end{tabular}
\end{minipage}
\end{document}


C should be replaced with c

-
Thank you. What is the difference between the lower and upper case c's anyway? – David Apr 23 '13 at 19:03
@David: The difference is the case, and LaTeX (like many programming languages) use a case-specific interface. So, just like you use \sin and not \Sin or \SIN. There is a difference, since LaTeX expects a lowercase l, c, r, p by default. tabularx provides an additional X, while array adds m and allow expansion of the defaults to your liking. – Werner Apr 23 '13 at 19:05