Mark the letter A, B, C or D on your answer sheet to indicate the sentence that best combines each pair of sentences in the following questions.
A flight attendant served us. She was very polite and patient.
A. A flight attendant, who served us, was very polite and patient.
B. A flight attendant which served us, was very polite and patient.
C. A flight attendant who served us was very polite and patient.
D. A flight attendant whom served us, was very polite and patient