72. A small object of mass m at 100℃ is placed into an equal mass of water at 0℃ in acalorimeter. The specific heat of the object is half that of the water. Assuming there areno energy transfer to the environment or to the calorimeter, the final equilibriumtemperature of the object plus water will be__________ .
(A) 25℃.
(B) 33℃.
(C) 50℃.
(D) 67℃.