An ideal gas is initially at P1,V1 is expanded to P2,V2 and then compressed adiabatically to the same volume V1 and pressure P3. If W is the net work done by the gas in complete process which of the following is true
a. W>0;P3>P1
b. W<0;P3>P1
c. W>0;P3<P1
d. W<0;P3<P1