P-V diagram of an ideal gas is shown in figure. Work done by the gas in the process ABCD is :

Question

$\begin {array} {1 1} (1)\;2P_{\circ}V_{\circ} & \quad (2)\;3P_{\circ}V_{\circ} \\ (3)\;P_{\circ}V_{\circ} & \quad (4)\;4P_{\circ}V_{\circ} \end {array}$