The word "option" means "choice". You can use it when you're talking about making a decision:

A: Where should we go?

B: I don't know. What are our options?

A: Why did you do that?

B: Because I had no other option!

"Option" is just a tiny bit more formal than "choice". For most situations, you can use either word. But there are some collocations that usually use "option" instead of "choice":

• explore your options
• examine your options
• keep your options open