The principle of vapour compression system is that fluids absorb heat while changing from a

• A. Vapour phase to liquid phase and give up heat in changing from liquid phase to vapour phase
• B. Liquid phase to vapour phase and give up heat in changing from a vapour phase to liquid phase
• C. Vapour phase to liquid phase only
• D. Liquid phase to solid state phase and give up heat in changing from a solid state to liquid phase