Detailed Solution:
The correct answer is “Buddhists”.
The award was announced by British prime minister Ramsay MacDonald on August 16, 1932, after the Round Table Conference (1930–32). It extended separate electorates to minorities, including Muslims, Sikhs, Indian Christians, Anglo-Indians, women, and the "depressed classes" (now known as the Scheduled Caste).
Therefore, the correct answer is option (4).