The gas stream exit temperature will be

Question

An industrial gas (Cp=1kJ/kgK) enters a parallel flow heat exchanger at 250⁰C with a flow rate of 2 kg/s to heat a water stream. The water stream (Cp=4kJ/kgK) enters the heat exchanger at 50⁰C with a flow rate 1 kg/s. the heat exchanger has an effectiveness of 0.75. the gas strem exit temperature will be                           

      (a) 75⁰C                          (b) 100⁰C                     (c) 125⁰C                        (d) 150⁰C