The correct answer is option 3: East India Company and Sir-ajuddaula. The battle of Plassey was fought between the East India Company, a British trading company, and Sir-ajuddaula, the Nawab of Bengal. The East India Company, under the leadership of Robert Clive, sought to establish control over Bengal, which was a prosperous region in India. Sir-ajuddaula, who had previously aligned with the French, was opposed to the British influence in the region. The battle took place on June 23, 1757. Despite being significantly outnumbered, the East India Company emerged victorious due to their strategic tactics and the betrayals within Sir-ajuddaula`s own army. The British victory in the battle of Plassey allowed them to gain control over Bengal and marked the beginning of British colonial rule in India.