"Assume zero rates and no dividends, the forward price is $$100.$ How to make an arbitrage trade if at $$101?"\text{'}"$buy$"\text{'}"$ or $"\text{'}"$sell$"\text{'}"[$a$]$ the call at $K=100$ for $[$b$]$ and $"\text{'}$buy$"\text{'}$ or $"\text{'}$sell$"\text{'}[$c$]$ the forward at $K=0$ net $e$ dollar today with no future liability."