An Ideal Monatomic Gas Originally in State a Is Taken

An ideal monatomic gas originally in state A is taken reversibly to state B along the straight-line path shown in the pressure-volume graph.

-What is the change in the internal energy,in calories,of the gas for this process?

A) zero calories
B) +12 cal
C) -110 cal
D) +110 cal
E) +122 cal