Problems with MS Forms Quiz

I'm fairly new to Forms.  I just spent several hours creating a 30 questions quiz on Forms and I'm having a problem.  If anyone knows the solution, it would be greatly appreciated.

On a couple of my multiple choice questions I want all the answers to be correct.  I checked the Multiple Answer toggle and put a green check mark next to all the choices, but when I previewed it with one choice selected, the question was marked wrong.  I did not toggle on Required.

If anyone knows how to fix these issues or what I'm doing wrong, your help would be greatly appreciated.

Here's a link to the quiz as it is now if that helps: 

https://forms.office.com/Pages/ResponsePage.aspx?id=j_Z4Rc2G-UqzF5Pjgmyg9SkKBk4YDT1Jr7DOGO29kHlUNkFOWVBENFdNQ1FFQUk5SEUyN01ON1NGMi4u

The questions which I want any answer correct are number 20 and 30.

Mark S

Dade Schools