An isolated system (a) is a specified region where transfer of energy and/or mass take place

An isolated system (A) is a region of constant mass and only energy is allowed to cross the boundaries
(B) is one in which mass within the system is not necessarily constant
(a) is a specified region where transfer of energy and/or mass take place
(C) cannot transfer either energy or mass to or from the surroundings
(D) none of the above.

Option E is the Correct answer. Explanation: An isolated system cannot transfer either energy or mass to or from the surroundings.