Udham Singh assassinated Michael O’Dwyer in London on March 13, 1940. O’Dwyer was the Lieutenant Governor of Punjab during the 1919 Jallianwala Bagh massacre and had publicly supported General Dyer’s actions. Udham Singh, who had witnessed the massacre as a child, spent over twenty years planning his revenge. He was subsequently tried and executed in July 1940. ANSWER: (B) Udham Singh