Which is a simple sentence?

Responses
A Why didn't you call me after you finished your chores?Why didn't you call me after you finished your chores?
B Can you help me with this, or should I ask someone else?Can you help me with this, or should I ask someone else?
C Did you know that we went to get ice cream after school yesterday?Did you know that we went to get ice cream after school yesterday?
D Are you going to the store with your mother or your sister this afternoon?

D Are you going to the store with your mother or your sister this afternoon?