Concept:The formation of Andhra Pradesh involved two key events: the creation of Andhra State in 1953 and the merger with the Telugu-speaking areas of Hyderabad State to form Andhra Pradesh in 1956 under the States Reorganisation Act.Explanation:Andhra State, carved out of Madras State, was formed on 1 October 1953 (option D). Later, on 1 November 1956, the States Reorganisation Act merged Andhra State with the Telugu-speaking regions of Hyderabad State, creating the present-day Andhra Pradesh. Therefore, the official formation year of Andhra Pradesh is 1956 (option A).Answer:The correct option is A (1956).