The correct answer is option 1, the Battle of Plassey. The Battle of Plassey, which took place in 1757, was a pivotal moment in the colonization of India by the British. In this battle, the British East India Company, led by Robert Clive, defeated the Nawab of Bengal, Siraj-ud-Daulah. This victory gave the British significant political power in the region. It allowed the British East India Company to establish a strong foothold in Bengal and gain control over its rich resources and trade routes. The Battle of Plassey marked the beginning of British dominance in India, paving the way for their subsequent colonization and eventual control over the entire Indian subcontinent.