Identity which of the following is a simple sentence:
a) You should listen to me, as I am your senior.
b) He drank 4 cups of coffee while waiting for his friend at the hotel.
c) After I complete the work I will submit it.
d) He went to the market?.
Ans. d) He went to the market?. - is a simple sentence. It has only one main clause whereas all other sentences are compound sentences with a main and one dependent clause.