She wanted to meet the director...........made an appointment with her

16. She wanted to meet the director...........made an appointment with her 
A, who        B. whom           C. which              D. that 
17. Here are my friends ......... I haven't met for ages 
A. whom        B. who        C. which         D. whose 
18. thhe doctors are worried about Mr.John's health  .......was sent to the hospital yesterday afternoon 
A. who         B. whom        C. X          D. that 
19. Dick bought the dictionary .......... was published in 1997 
A. who           B. whom         C. which          D. X
20. This is my aunt ........... you met some days ago 
A. who              B. whom               C. that               D. X