Since this is a cyclic process:- Change in internal energy=0. In the process C-A the work done W is zero, thus the heat Q is zero since it is an isochoric process.
Next in the process A-B, I got the heat Q to be equal to 0.5 L-atm and Work done W equal -0.5 L-atm . (Area under the graph and expansion of gas gives negative work done here)
For the process B-C its given Work done W is 1 L-atm (Positive since compression) and since change in internal energy =0, the heat must be negative of work done thus Q = -1 L-atm
Therefore the total heat exchange corresponding to each process should be -1+0.5+0=-0.5. The absolute value being 0.5 L-atm.
But the answer gives 1.5 L-atm as the total heat exchange. How? Please explain