You should be ashamed . . . . . . . . your misconduct.

A. to

B. by

C. at

D. of

Answer: Option D

Solution(By Examveda Team)

Ashamed means embarrassed or guilty because of one's actions. The word is followed by the preposition 'of', to denote the action to cause the guilt. Hence, 'of' is the correct answer for the given blank.