Correct answer: A. Prices were controlled to maintain a large army at lower cost
Explanation: The direct answer is option A: prices were controlled so that a large army could be maintained at lower cost. Military economics means arranging income, prices, supplies, and wages so that the state can support its armed forces. Alauddin Khalji wanted a large and effective army to defend the Sultanate and expand its power. If market prices remained low and controlled, soldiers could buy food, clothing, and other necessities with their fixed salaries. The ruler could therefore maintain a large army without constantly raising military pay. The administration watched markets, fixed prices, and punished dishonest traders or hoarders. Option A is correct because it connects price control directly with the cost of maintaining soldiers. Option B is wrong: the policy was not introduced to raise prices or decorate temples. Option C is wrong: markets were not closed to stop foreign travellers; they continued functioning under regulation. Option D is wrong because Nalanda and the navy were unrelated to Alauddin Khalji’s market policy. Exam cue: when market control appears with Alauddin Khalji, connect it with cheap supplies, fixed salaries, and a large army.