Correct Answer: Because of low atmospheric pressure

Solution : The correct option is Because of low atmospheric pressure .

At higher elevations, the decrease in atmospheric pressure causes a reduction in the boiling point of water. Boiling occurs when a liquid's vapour pressure matches the atmospheric pressure. With lower atmospheric pressure at higher altitudes, water molecules can more easily transition into vapour. As a result, less energy is required to reach the boiling point, leading to a lower boiling temperature.