This could be a tough question to answer if you are not able to work nights. Answering this question with a 'no' isn't necessarily a deal breaker. The interviewer may know of a day shift opening in a few weeks and will keep your name on the back burner until then. Or, the interviewer may be able to work with your shift request. You need to be honest so that you guarantee you're ending up in a role that will suit your scheduling needs.
"I currently work a day shift, 7 am to 5 pm. I am seeking a role with the same schedule. With that said, I am a team player, and can certainly pick up the odd night shift to cover someone when needed."
"As I am new to my career as a physician assistant, I believe that I should make myself available for any shift options. Could you provide me with further details on your night shifts?"
"I am available for a variety of shifts. Could you share with me the rotation here?"