The explanations are mentionned in the attached file.
11. The right answer is D.
12. The right answer is C.
13. The right answer is B.
14. The right answer is A.
15. The right answer is B
16. The right answer is C
17. The right answer is A.
18. The right answer is D.
19. The right answer is D.
20. The right answer is B.
21. The right answer is B.
