The Buxar War of 1764, a decisive battle that established British supremacy in India, was fought against a combined force that included the ruler of which state?

British colonial rule over India. The wording of the question specifically requires the association represented by Awadh. Option A (Mysore) is incorrect because it does not match the specific person, district, place, institution, event or factual association asked in the question. Option B (Maratha Confederacy) is incorrect because it does not match the specific person, district, place, institution, event or factual association asked in the question. Option D (Hyderabad) is incorrect because it does not match the specific person, district, place, institution, event or factual association asked in the question. The Battle of Buxar was fought on October 22, 1764, at Buxar (Baksar) in Bihar between the British East India Company and a combined force consisting of Mir Qasim (Nawab of Bengal), Shuja-ud-Daula (Nawab of Awadh), and Shah Alam II (Mughal Emperor). The British forces were led by Hector Munro. The victory of the British in this battle was even more decisive than the Battle of Plassey (1757) because they defeated three major Indian powers simultaneously. Following this victory, the Treaty of Allahabad (1765) was signed, under which the British received the Diwani (revenue collection rights) of Bengal, Bihar, and Orissa from Shah Alam II. Mysore was ruled by Hyder Ali and later Tipu Sultan; they were defeated by the British in a separate series of four Anglo-Mysore Wars. The Maratha Confederacy was weakened through the three Anglo-Maratha Wars. Hyderabad was ruled by the Nizams who generally maintained a subsidiary alliance with the British. The Battle of Buxar is considered a turning point in the establishment of British colonial rule over India.