On the common app, the UD writing supplement is optional. There are three questions, and two of them I can answer. The third one I cannot and I was wondering if it would hurt my admission chances if I just answered two of the three.
In the world of college apps, “optional” means mandatory. With so many applications to compete with, you really shouldn’t leave anything to chance. It could come down to you and one other applicant that answered that third question. I don’t know what the question is, but if you can’t come up with any answer at all, I would at least state that you can’t answer the question and then explain why.