A system is enclosed in a piston-cylinder device and undergoes expansion or compression (i.e., a closed system). The work performed by the device to the system can be calculated by = (Vfinal-Vinitial)

a. when the system is the ideal gas.

b. when the surrounding's temperature is constant.

c. when the pressure exerted on to the system is constant.

d. when the final volume is larger than the initial volume

(choose a,b,c, or d)