Choose the best option A, B, C, or D on your answer sheet to indicate the sentence that is CLOSEST in meaning to each of the following questions.
He couldn’t come to the conference because he was seriously ill.
A.His illness was very serious that he couldn’t come to the conference.
B.Although he was ill, he came to the conference.
C.He couldn’t come to the conference, so he became seriously ill.
D.Because of his serious illness, he couldn’t come to the conference.