Editing the "Choices" text box in multiple choice questions

I see - do that in the slide master, right? I note that it fixes the immediate issue of not being able to see most answers. It still reverts to a small box when I try to resize it after making the change, but I think I found a solution in conjunction with this one:

I found that when I moved the text box above the answer choice box down, for some reason, it interacted with the answer box, and it suddenly showed all the answers again. After saving it, it appears to have kept the choice boxes intact and in the positions I want them to be in. I'm crossing my fingers that this will be the solution for the moment.

In the meantime, I'm making a note not to use this particular template again. Thanks for your help, Sandeep!