Explain clearly

A firm's short-run supply curve is given by s(P) = 0 (if p $20 > compensating variation O B. His demand curve is down-ward sloping, and equivalent variation = $20 = compensating variation O C. His demand curve is down-ward sloping, and equivalent variation > $20 > compensating variation 0 D. His demand curve is vertical, and equivalent variation = $20 = compensating variation