xsim 多项选择重复字母，指定为 \correct

Question

为什么弹出的是 (C) 而不是 (D)。(D) 应该是正确的解决方案。代码从 xsim 手册复制/粘贴。

\NewTasksEnvironment[label=(\Alph*),label-width=15pt]{choices}[\choice]
\newcommand*\correct{\thetask\expanded{\SetExerciseProperty{choice}{\thetask}}}

\begin{exercise}
The system of units that is based on the powers of 10 is called 
    \begin{choices}(1)
        \choice US System of Units
        \choice EU System of Units
        \choice Imperial System
        \choice[\correct] The Metric System
    \end{choices}
\end{exercise}
\begin{solution}
    \GetExerciseProperty{choice}
\end{solution}

Answer 1

尝试将宏的定义更改\correct为

\newcommand*\correct{\refstepcounter{task}\thetask\expanded{\SetExerciseProperty{choice}{\thetask}}}

（可能是tasks包改变了它的行为；当用户使用自定义标签时，原始标签的计数器不应该增加，这是有道理的。）

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另一方面，我不确定为什么需要将“ \correct”放在括号内。对我来说，这样做更有意义

\NewTasksEnvironment[label=(\Alph*),label-width=15pt]{choices}[\choice]
\newcommand*\correct{\expanded{\SetExerciseProperty{choice}{\thetask}}}

\begin{exercise}
The system of units that is based on the powers of 10 is called 
    \begin{choices}(1)
        \choice US System of Units
        \choice EU System of Units
        \choice Imperial System
        \choice\correct The Metric System
    \end{choices}
\end{exercise}