I was astonished at his behaviour.
A. His behaviour is astonishing to me.
B. His behaviour astonished me.
C. His behaviour are astonished me.
D. His behaviour had astonished me.
Answer: Option B
Solution (By Examveda Team)
His behaviour astonished me.Given sentence is in simple past tense and it is in passive voice.
Rule :
Subject + V3 + Other agents

b & c are same