An ideal gas is taken through the cycle $\;A \to B \to C \to A \;$ as shown in the figure . If the net heat supplied to the gas in the cycle is 5 J , the work done by the gas is the process $\;C \to A\;$ is

Question

$(a)\;-5\;J\qquad(b)\;-10\;J\qquad(c)\;-15\;J\qquad(d)\;-20\;J$