Effendy : 1. Do nothing, until January 17 next year; you need 0.04 million (400x100 shares). Then I owned 100 Tesla shares. If the stock price is higher than 400 by then, congratulations. (4xx (per share) - 400) x 100 is your profit.
2. Tesla continues to be above 400, and your call's options will continue to rise. You sell 400call and make the difference in price. The 400call option premium is now 28, and when you buy it, it's 17.50; (28 - 17.5) x 100 is your profit.

Effendy : I believe then your option is sold off?

Effendy sam li OP : I'm not talking about you, I'm replying to the above

Effendy 唯一了 : Options (Basic 4 combinations)
Call / Put
Buy / Sell
Each option = 100 shares
Buy Call (Bullish) - you expect price to keep going up so you buy a call to lock at a current/lower price. You pay the premium. You want to buy so you should expect to have the cash to pay for the shares when the option expires in the money (ITM).
Sell Call (Bearish) - you expect price to keep going down so you sell a call to lock at current price/higher price. You collect the premium. You should have 100 shares or at least have the money to buy 100 shares when the option expires in the money (ITM).
Buy Put (Bearish) - you expect price to keep going down so you buy a put to lock at current price/higher price. You pay the premium. You should have 100 shares or at least have the money to buy 100 shares when the option expires in the money (ITM).
Sell Put (Bullish) - you expect price to keep going up so you sell a put to lock at a current/lower price. You collect the premium. You want to buy so you should expect to have the cash to pay for the shares when the option expires in the money (ITM).
In short, buying any call or put means you pay the option premium. Selling any call or put means you collect the option premium.
If you do not have the shares or the money to buy the shares when options expires in the money (ITM), then you can buy and sell back the options to collect the differences between what you paid/collect vs what you gain/lost.
Check out MooMoo’s tutorial on options in their learning for the basics on options.

Effendy : I didn't understand your question.