# How to “bubble in”/color fill an item counter ((A),(B),(C),…) in an enumerated list

I'm trying to make an answer explanation guide for a test where the correct answer is "bubbled in".

I've tried using the enumitem package and tikz as shown in this post (Enumerated list with blue circles and number inside it), but it's messing up the default spacing and the counters of the other answer choices. This is what I have so far:

\documentclass{article}
\usepackage{tikz}

\newcommand*\circled[1]{\tikz[baseline=(char.base)]{%
\node[shape=circle,fill=blue!20,draw,inner sep=2pt] (char) {#1};}}

\usepackage{enumitem}

\begin{document}
\renewcommand{\labelenumi}{(\Alph{enumi})}
\begin{enumerate}
\end{enumerate}

\end{document}


Ultimately what I want is something like this:

A transparent fill color would be nice. Thanks for any help.

-

You don't have to specify:

[label=\circled{(\Alph*)}]


but only:

[\circled{\Alph{enumi}}]


Moreover, it is also needed to advance the counter.

Therefore:

\documentclass{article}
\usepackage{tikz}

\newcommand*\circled[1]{\tikz[baseline=(char.base)]{%
\node[circle,fill=blue!20,draw,inner sep=2pt,opacity=0.5,text opacity=1] (char) {#1};}}

\def\cnt{\stepcounter{enumi}\Alph{enumi}}

\usepackage{enumitem}

\begin{document}
\renewcommand{\labelenumi}{(\Alph{enumi})}
\begin{enumerate}
\end{enumerate}

\end{document}


gives:

-

A different approach. The main problem with this solution is that the placement of the circle is too "manual", and different fonts would require a new manual adjust.

\documentclass{article}
\usepackage{tikz}
\usepackage{enumitem}

\newcommand\correct{%
\tikz[overlay]\fill[fill=green!50!black, opacity=.2] (-3ex,.6ex) circle (2ex);%
}

\begin{document}
\renewcommand{\labelenumi}{(\Alph{enumi})}
\begin{enumerate}
\end{enumerate}
\end{document}


-
Thanks! Way better than what I was settling for. –  Nelson Feb 20 '13 at 15:50
You can play with \labelsep to get the the right placement with less of trial-end-error. –  tohecz Feb 20 '13 at 16:52

Another option, defining a dedicated command \citem and using the features provided by enumitem (instead of manually redefining \labelenumi):

\documentclass{article}
\usepackage{enumitem}
\usepackage{tikz}

\newcommand*\circled[1]{\tikz[baseline=(char.base)]{%
\node[circle,fill=blue!20,draw,inner sep=2pt,opacity=0.5,text opacity=1] (char) {#1};}}

\newcommand\citem{%
\stepcounter{enumi}\item[\circled{\Alph{enumi}}]}

\begin{document}

\begin{enumerate}[label=(\Alph*)]