\documentclass[onepage]{webquiz}
\title{An answer with comparison=complex}
\begin{document}
  \begin{question}     % a quiz question
     If $a=3-i$ and $b=2+i$ then what is $ab$?
     \answer[complex]{7+i} (Correct answer $7+i$)
  \end{question}
  \begin{question}     % a quiz question
     If $a=3-i$ and $b=2+i$ then what is $ab$?
     \answer[complex]{7+i} (Correct answer $7+i$)
  \end{question}
\end{document}