Final answer:
The British began asserting political power in India after the East India Company's victory at the Battle of Plassey in 1757. This event preceded the Sepoy Rebellion of 1857, which ultimately led to the establishment of direct British rule, known as the British Raj. The correct option is D.
Step-by-step explanation:
The British began to assert political power in India following the East India Company's victory at the Battle of Plassey in 1757. This victory marked a significant shift in power, allowing the British East India Company to establish itself as the main power broker in India and subsequently control vast territories.
Later developments, such as the Sepoy Rebellion of 1857—also known as the Indian Mutiny—greatly influenced the political landscape. The rebellion was a pivotal event that led to direct British governance over India, known as the British Raj, after the British government abolished the East India Company due to its failure to manage the unrest effectively.
The partition of Bengal and the passage of the Rowlatt Bills occurred much later and were not the initiators of British political power in India, but rather subsequent actions during the period of British control.