A trader sells one European put option contract with a strike price of $$40$ and a time to maturity of six months. The put option price is $$2.$ If the price of the underlying asset is $$39$ in six months. What is the trader's gain or loss?

$($a$)$ gain $=100$

$($b$)$ gain $=200$

$($c$)$ loss $=100$

$($d$)$ loss $=300$