The correct answer is option 1, the Morley-Minto Reforms of 1909. These reforms, also known as the Indian Councils Act of 1909, introduced separate electorates for different religious communities in India. The provision for a separate electorate for Muslims was a significant development in the political representation of the Muslim community.

Option 2, the Montagu-Chelmsford Reforms of 1919, did not include any provision for separate electorates. These reforms focused on introducing limited self-government in India, but did not specifically address the issue of separate electorates.

Option 3, the Communal Award of 1932, also introduced separate electorates for various religious communities in India, including Muslims, Sikhs, and others. However, this was not the first instance of separate electorates for Muslims.

Option 4, the Government of India Act of 1935, did introduce separate electorates, but this was for scheduled castes (Dalits) and not specifically for Muslims.

Therefore, the correct answer is option 1, the Morley-Minto Reforms of 1909, as this was the first introduction of separate electorates for Muslims in India.