Final answer:
The correct answer is [b] introduction of separate electorates, which was a major change implemented by the Indian Councils Act of 1909 to propagate the British divide and rule strategy by deepening religious divisions within Indian society.
Step-by-step explanation:
Indian Councils Act of 1909
The Indian Councils Act of 1909, commonly known as the Morley-Minto Reforms, is associated with one major change that propagated the British agenda of divide and rule. The correct answer to the student's question is [b] introduction of separate electorates. This act allowed for members of different religious communities to elect their own representatives, thus deepening the divisions within Indian society. This policy focused Indians on their religious differences and had long-term disastrous results down to the present day. It was a strategic move that was designed to cause division and thereby weaken the Indian independence movement by pitting different religious communities against each other.
While the Act introduced several reforms, the establishment of separate electorates was particularly instrumental in cementing the divide between Hindus and Muslims, which played into the British strategy of maintaining control over India. Separate electorates meant that Muslims and Hindus would vote separately for their respective community candidates, ensuring that the colonial power could manipulate these divisions to their advantage. The political landscape of India was further complicated by the introduction of such divisive policies, which is evident in the tensions and communal politics that prevail in some regions of South Asia to this day.