Mark the letter A, B, C, or D on your answer sheet to indicate the sentence that is closest of the following questions

Mark the letter A, B, C, or D on your answer sheet to indicate the sentence that is closest of the following questions.
46. The doctor is working here. I admire him so much.
A. The doctor which I admire so much is working here. B. The doctor whose I admire so much is working here.
C. The doctor whom I admire so much is working here. D. The doctor is working here who I admire so much.
47. They last ate raw fish two weeks ago.
A. They have eaten raw fish for two weeks.
C. They haven't eaten raw fish for two weeks.
48. "We can go to the airport by taxi this morning", they said.
A. They said they could go to the airport by taxi that morning.
B. They said they can go to the airport by taxi that morning.
C. They said we can go to the airport by taxi this morning.
D. They said we could go to the airport by taxi that morning.
49. I didn't know that Joe had to get up early, so I didn't wake him up.
A. If I had known that Joe had to get up early, I would have woken him up.
B. If I had not known that Joe had to get up early, I would not have woken him up.
C. If I knew that Joe had to get up early, I would woke him up.
D. If I know that Joe had to get up early, I will wake him up.
50. No one has sent me that letter.
A. I haven't been sent that letter.
C. I haven't sent that letter.
B. They ate raw fish since two weeks.
D. They didn't eat raw fish since two weeks.
B. I wasn't sent that letter.
D. That letter has sent to me by no one.