He took a momentous decision in this case.

A. transient

B. important

C. wrong

D. hopeless

Answer: Option B

Solution(By Examveda Team)

Transient : lasting only for a short time; impermanent.
Important : of great significance or value.
Wrong : not correct or true; incorrect.
Hopeless : feeling or causing despair.
Momentous : of great importance or significance, especially in having a bearing on future events.

Synonym of Momentous is Important