How to "bubble in"/color fill an item counter ((A),(B),(C),...) in an enumerated list

Question

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}
\item Answer A
\item[label=\circled{(\Alph*)}] Answer B
\item Answer C
\item Answer D
\item Answer E
\end{enumerate}

\end{document}

Ultimately what I want is something like this:

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

Answer 1

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}
\item Answer A
\item Answer B
\item[\circled{\cnt}] Answer C
\item Answer D
\item Answer E
\end{enumerate}

\end{document}

gives:

Answer 2

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}
  \item Answer A
  \item\correct Answer B
  \item Answer C
  \item Answer D
  \item Answer E
\end{enumerate}
\end{document}

Answer 3

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*)]
\item Answer A
\item Answer B
\citem Answer C
\item Answer D
\item Answer E
\end{enumerate}

\end{document}