short forward

问题如下：

What is the payoff from a portfolio consisting of a short forward contract with maturity T and a long call option with maturity T? Assume that the strike price for the option is the forward price.

选项：

解释：

The payoff is

$K - S_T + max(S_T - K,0) = max(0,K - S_T)$

To make sure you understand why this is true, you should consider the ST > K and the ST < K cases separately. The payoff is the payoff from a long put option with a strike price equal to the forward price.