One who sacrifices his life for a cause

A. Soldier

B. Revolutionary

C. Martyr

D. Patriot

Answer: Option C

Solution(By Examveda Team)

One word substitute is Martyr.

Soldier: a person who serves in an army.
Revolutionary: involving or causing a complete or dramatic change.
Martyr: a person who is killed because of their religious or other beliefs.
Patriot: a person who vigorously supports their country and is prepared to defend it against enemies or detractors.