Two moles of a perfect gas undergoes following processes: \[\] 1. A reversible isobaric expansion from (1 atm, 20L) to (1 atm, 40L)\[\] 2. A reversible isochoric change of state from (1 atm, 40L) to (0.5 atm, 40L)\[\] 3. A reversible isothermal compression from (0.5 atm, 40L) to (1atm, 20L)\[\] Calculate the total work done involved in the above processes

Question

$\begin {array} {1 1} (A)\;343\: J & \quad (B)\;-620.96 \: J \\ (C)\;-343\: J & \quad (D)\;620.96 \: J \end {array}$