documentclass{article}
usepackage{pgffor}
usepackage{enumitem}

newcommandAnswersList{}
newcommandAddAnswer[1]{edefAnswersList{AnswersList#1endgraf}}

newcommand*{mc}[6]{%
    % code to display the multiple choice for #1...#5
    AddAnswer{#6,}%
}%

begin{document}

mc{2}{3}{5}{7}{11}{3}
mc{2}{3}{5}{7}{11}{5}


The list of answers are:

begin{enumerate}[label=(arabic*)]
foreach answer in AnswersList {%
    item answer
}%
end{enumerate}
end{document}