A system is taken from state A to state B through three different paths 1 , 2, 3 . The work done is minimum in

$(a)\;process\; 1\qquad(b)\;process\;2\qquad(c)\;process\;3\qquad(d)\;process\;4$

Explanation :
Work done = Area under the P - V curve . Which is maximum for process 1 .