Why did my question have automatically duplicated option?

[Vananh303]

I made a quiz on MS Form and gave it to my students. When they did the quiz without any problems.
When I recieved the result, I found out some of questions have more options than that I had made. The options had been duplicated.
My students chose the duplicated one and they were not be marked. Some students had this problem, the other did not.
I really want why this happended and how to fix this.

This is what I madeThese are questions I made

The review of my student who doesn't have problem

This is review of my student's work. The questions and answers are normal.

The review of my student who had this problem. He chose the duplicated answer and he had no point for this.