What Should You Do When You Cannot Respond to a Request

Multiple Choice

What should you do when you cannot respond to a request made in an email?

A) Log off the system so the sender will assume that you are offline.
B) Set up an automated response to say that you are out of town.
C) Inform the sender that you are busy and cannot reply straightaway.
D) Reply immediately to explain how soon you can respond in full.
E) Ignore the email for now and reply when you can.