A thermodynamic cycle

Question

Common Data for Question 1(1) & 1(2)

A thermodynamic cycle with an ideal gas working fluid is shown below.

1. (1) The above cycle is represented on T-S plane by       

1. (2)    If the specific heats of the working fluid are constant and the value of specific heat ratio $\gamma$ is 1.4, the thermal efficiency (%) of the cycle is                                                       

      (a) 21                                                                  (b) 40.9

      (c) 42.6                                                               (d) 59.7