a) law of conservation of mass only
b) law of conservation of energy only
c) law of conservation of mass and energy
d) third law of thermodynamics only

Answer: c
Explanation: Law of conservation of mass applies to each component entering the process. For example, amount of milk entering through pasteurization inlet should be equal to amount of milk leaving the pasteurization outlet. Similarly, law of conservation of energy applies where total energy in the material entering the process plus energy added in the process must be equal to total energy leaving the process.