Error in responding to students' answers

[Cherry217]

My student did a quiz in MS Forms. He answered correctly, Forms marked it right but gave him 0. Can anyone help me? Thanks

[#2]

@Cherry217 .I could not the language in photo. so could translate in English language, take photo , upload here 

[#3]

@Cherry217 could you provide the detail steps that can reproduce this issue so that we can do further investigation?