I take it automatic regrading is impossible, but I'd like the feedback to show the correct answer.
I'm not fully confident I understand what you're seeking, but let me see if a couple guides can help.
Regrade:New QuizzesHow do I regrade an assessment question in New Quizzes?
Classic QuizzesWhat options can I use to regrade a quiz in a course?
How do I add feedback to an assessment question in New Quizzes?
Manage Feedback Settings How do I manage settings for an assessment in New Quizzes?
Mange Feedback Settings What options can I set in a quiz?
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