Answer:
c. The law of conservation of energy
Step-by-step explanation:
The famous "law of conservation of Energy" states that energy inside an isolated system remains conserved. It can not be created and can't be destroyed as well. The energy can only be moved or transformed into another form.
This can be proved using "Noether's Theorem". Classically, only energy was considered conserved but Special Relativity proved that even mass is conserved as it showed the relation between mass and energy.