What is the principle of a calorimeter?

• A. Heat loss rate is directly proportional to temperature difference
• B. The total heat lost by a hot body is same as the total heat gained by the cold body provided no heat is lost to the surroundings
• C. Heat loss depends only on specific heat of a substance
• D. For the same amount of heat flow from a sample to two different samples of same mass is a product of their specific heats and temperature difference