Why is Shimla cooler than plain areas?

Correct answer: Due to higher altitude

Direct answer: Option C, due to higher altitude. Altitude means height above sea level. As altitude increases in the lower atmosphere, air pressure decreases and the air is generally cooler, so hill stations such as Shimla usually have lower temperatures than nearby plains. The reasoning is: Shimla is located at a much greater height; temperature generally falls as height increases; therefore Shimla is cooler. Option C correctly identifies the main climatic control in this comparison. Option A, low rainfall, is not the basic reason stated here and rainfall alone does not determine temperature. Option B is wrong because Shimla is not made cooler simply by being near the sea. Option D is wrong because population does not explain the normal difference in temperature between a hill station and the plains. The comparison is about relief or altitude, not people. Memory cue: as height rises, temperature generally falls.