Which choice best describes the sentence and explains how to improve it? After taking tickets and helping the guests find their seats, Sergio sat in the back and enjoyed the concert.

A. This sentence is complete and correct. It does not need any revision.

B. This is a comma splice. Change the comma to a period to make two complete sentences.

C. This is a fragment without a predicate add a verb to show what the subject is doing.

D. This is a rambling sentence. Eliminate some conjunctions. Mix short and long sentences.