Step 1: Historical background.
The All India Muslim League was established in Dhaka (now in Bangladesh) in 1906. It played a major role in the demand for a separate Muslim nation, which eventually led to the formation of Pakistan.
Step 2: Options analysis.
(A) 1902: Incorrect.
(B) 1906: Correct — founded in Dhaka in 1906.
(C) 1911: Incorrect.
(D) 1912: Incorrect.
Step 3: Conclusion.
The Muslim League was established in 1906.