Which of the following P-V curve represents maximum work done?

Work done in an expansion process is given by the area under the P-V curve. Graph C represents a cyclic process (or closed loop) where net work done is the area enclosed by the cycle, which is positive for clockwise cycle, whereas A, B, D are open paths. Actually, let's look at graph C: it's a closed cycle representing positive work done (area enclosed), making it maximum compared to open paths or let's re-verify options C and D.