How to create answer(key) review in quiz app .please help me

how to create answer review(key) in quiz app .i have created but in this i m facing problem .if user saved own answer and aftere some times user again go that question where user saved own answer and changed won answer i mean user edit own answer that question if user is doing like that then updated answer is not showing in my answer key still previous changed question is showing .please tell me how to show users updated answer.below is all blocks

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