Correct Option: A

The Battle of Buxar was fought on 23 October 1764 between the forces under the command of the British East India Company led by Hector Munro, and the combined Muslim army of Mir Qasim, the Nawab of Bengal; Shujaud-Daula the Nawab of Awadh and the Mughal King Shah Alam II. The prime victim Shah Alam II, signed the Treaty of Allahabad that secured Diwani Rights for the Company to collect and manage the revenues of almost 100,000,000 acres of real estate which form parts of the modern states of West Bengal, Orissa, Bihar, Jharkhand, and Uttar Pradesh, as well as areas in the neighbouring country of Bangladesh. The Treaty of Allahabad heralded the establishment of the rule of the East India Company in one-eighth of India proper with a single stroke. The battles of Plassey and Buxar secured a permanent foothold for the British East India Company in the rich province of Bengal and secured its political ascendancy in the entire region later to be named India.