Step 1: Background.
The Muslim League under Muhammad Ali Jinnah demanded the creation of Pakistan as a separate nation. To press this demand, the League announced a "Direct Action Day."
Step 2: Date of observance.
Direct Action Day was observed on 16th August, 1946. It led to widespread communal riots, most notably the Great Calcutta Killings.
Step 3: Elimination.
- (A) 1945 dates: Incorrect, as the call for Direct Action was made in 1946.
- (B) 16th August, 1946: Correct.
- (C) 17th August, 1945: Incorrect.
- (D) 17th August, 1946: Incorrect, since it was on the 16th.
Step 4: Conclusion.
Thus, the Muslim League observed Direct Action Day on 16th August, 1946.