A heat transformer is a device that transfers a part of the heat, supplied to it at an intermediate temperature, to a high temperature reservoir while rejecting the remaining part to a low temperature heat sink. In such a heat transformer, 100kJ of heat is supplied at 250 K. The maximum amount of heat in kJ that can be transferred to 400K, when the rest is rejected to a heat sink at 300K is
(a) 12.50 (b) 14.29
(c) 33.33 (d) 57.14