I need these questions. Will give thumbs up! :

1. What's the profit of a call option that is At The Money at expiration? (Simplify the answer as much as possible)

2. What's the profit of a short put option that is At The Money at expiration? (Simplify the answer as much as possible)

3. What's your maximum gain if youre short a call option and long the corresponding put option? (Same underlying asset, same strike price, same expiration date) (Simplify the answer as much as possible)