The question asks to match revolutionary figures from the Indian independence movement with their significant contributions or events. The correct historical associations are crucial for answering this question. - The Jallianwala Bagh massacre took place on April 13, 1919, in Amritsar, Punjab. - General Reginald Dyer ordered his troops to fire on an unarmed crowd. - Sir Michael O'Dwyer, as the Lieutenant Governor, was the administrative head of the province and was seen as having approved or condoned Dyer's action. - Udham Singh, who was present at Jallianwala Bagh, vowed revenge and waited for over two decades to carry it out.