(a)The source of energy that can be regenerated in nature is known as renewable source of energy. E.g - sun, wind etc.The source of energy that does not regenerate in nature is known as non-renewable source of energy.
Eg- coal, pretloleum.
(b)Exhaustible sources are those sources of energy which will exhaust or dissappear after some time. Eg - coal, petroleum. Inexhaustible sources are those sources of energy, which will not exhaust from nature. These are unlimited source of energy. Eg - sun
Therefore, we can say that, (a) and (b) are almost the same.
hope it helps.. :))