Correct answer: A. Operation Polo
Explanation: The direct answer is A, Operation Polo. After India became independent, Hyderabad was a princely state whose ruler had not joined India. Negotiations did not resolve the issue, so in September 1948 the Indian government conducted a short military-police action called Operation Polo, also known as the Hyderabad Police Action. Sardar Vallabhbhai Patel, the Deputy Prime Minister and Home Minister, was closely associated with integrating princely states. Option A is correct because Operation Polo brought Hyderabad into the Indian Union. Option B, Operation Blue Star, was a 1984 military operation at the Golden Temple in Amritsar. Option C, Operation Vijay, is associated with other Indian military actions, especially the 1999 Kargil conflict, not Hyderabad's 1948 integration. Option D, Operation Meghdoot, began in 1984 in the Siachen region. Memory cue: Patel plus Hyderabad equals Operation Polo.