Assertion (A): A thermodynamics system may be considered as a quantity of working substance with which interaction of heat and work are studied.
Reason (R): Energy in the form of work and heat are mutually convertible
a) Both A and R are individually true and R is the correct explanation of A
b) Both A and R are individually true but R is not the correct explanation of A
c) A is true but R is false
d) A is false but R is true