Restrict question deletion when answers exist

I'm using Apache Answer and would like to prevent question authors from deleting their questions if there are existing answers.
Is there a way to configure this behavior, either through admin settings or available plugins?

No file, test, or entry point is named. Start by tracing question deletion and reviewing existing admin settings and plugin extension points; clarify whether the desired behavior should be built in or provided by a plugin. Completion requires an agreed mechanism for preventing authors from deleting questions that have answers.

Written by the indexing model from the issue text.