Answer : (b) negative
Explanation :
The above graph depicts the process of expansion & compression . Since , for an adiabatic process the slope is $\;r(=\large\frac{Cp}{w})\;$ times the slope incase of isothermal process ,
$|w_{2}| > |w_{1}|$
So , the compressive work is more .
Total work done = |w_{1}|-|w_{2}| < 0