Web development: Help me to fix this code please.

Purpose:

Submit Answer button: User must choose one of the three radio buttons then finalize their answer by clicking on the Submit Answer button. Once the Submit Answer is clicked, you cannot click on the Submit button again, as the final answer is submitted. After the answer is submitted, color code will tell the user whether they get the answer correct or not. Green means the answer is correct, red means the answer is incorrect.

Next Question button: User must submit the answer first before going into the next question. If the user is yet to press "Next Question", an alert message will pop up, which says "You have not completed this question yet."

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Instruction: Please fix the source code and post the fixed code on Chegg, do NOT screenshot or write it on paper, just copy and paste them onto Chegg. Also, screenshot website for proof.

Source code is listed below, please help me to fix:

Source file name: test.html

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Question 1 of 4 What is 36 + 42 64 78 ? lchose 78 76 Then, I click Submit Answer Submit Answer Next