The correct options are
A The massacre prompted the Muslim Khilafat movement to protest against the British.
B The Indian leaders condemned the British for this tragedy.
C Udham Singh attacked Michael O'Dwyer, the Directory General of Amritsar who was believed to be responsible for the massacre.
The massacre sparked outrage and was condemned by luminaries across India. The Muslims were enraged by the killings and revived the Khilafat Movement to fight against the British. Twenty-one years later, Udham Singh, an Indian freedom activist attended an event in Caxton Hall in London which was attended by Michael O'Dwyer, the Lieutenant Governor of Punjab who is believed to have given the order to fire upon the protesters. He shot Dwyer to death in Caxton Hall, London on 13th March 1940. It led to launch of Non cooperation movement.