Concept:Sardar Udham Singh assassinated Michael O'Dwyer, the former Lieutenant Governor of Punjab, to avenge the Jallianwala Bagh massacre.
Explanation:Udham Singh was a revolutionary from the Ghadar Party.
On 13 March 1940, he shot Michael O'Dwyer in London.
O'Dwyer was the lieutenant governor of Punjab during the 1919 Jallianwala Bagh massacre.
Udham Singh considered O'Dwyer responsible for the massacre.
He was arrested, tried, and hanged in July 1940.
While in custody, he used the name Ram Mohammad Singh Azad to represent Punjab's three major religions and his anti-colonial spirit.
He is remembered as Shaheed-i-Azam Sardar Udham Singh.
Answer:Michael O'dwyar (Option B)