A solid metallic cube of heat capacity s is at temperature 300 k. it is brought in contact with a reservoir at 600 k. if the heat transfer takes place only betw

A solid metallic cube of heat capacity S is at temperature 300 K. It is brought in contact with a reservoir at 600 K. If the heat transfer takes place only between the reservoir and the cube the entropy change of the universe after reaching the thermal equilibrium is (A) 0.69 S (B) 0.54S (C) 0.27 S D) 0.19s