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.
John was not here yesterday. Perhaps he was ill.
A. John needn’t be here yesterday because he was ill
B. Because of his illness, John shouldn’t have been here yesterday
C. John might have been ill yesterday, so he was not here
D. John must have been ill yesterday, so he was not here