Lord Chelmsford was the Viceroy of India from 1916 to 1921. His administration was responsible for the enactment of the repressive Rowlatt Act and the subsequent implementation of martial law in Punjab, which culminated in the Jallianwala Bagh massacre on April 13, 1919. His tenure is marked by a shift from constitutional reforms to extreme colonial repression. ANSWER: (B) Lord Chelmsford