You are confident that the pound will increase against the U$.$S$.$ dollar, so you purchase a call option on the pound with a strike price of $$116($currency price is quoted as $100$ times the exchange rate$).$ When you purchase the option the spot price is $$116,$ and the pound move to $$120.$ The currency option expires $"$in the money." Your gross profit is $ $\_\_\_\_\_\_\_\_\_\_.$