Given below are two statements, one is labelled as Assertion (A) and the other one labelled as Reason (R):
Assertion (A): The Clausius statement of second law of thermodynamics states that it is impossible to transfer heat from a body at low temperature to a body at high temperature without the aid of external work.
Reason (R): Heat always flows from low temperature to high temperature.
In light of the above statements, choose the correct answer from the options given below: