Option agreements. How long?

So how long does a publisher have to decide if they want to publish a game after receiving a prototype? I still think they have plenty of time before I bring this up with them but for some reason until they decide I feel it’s better to shop my newer games around with different companies. They are a big publisher with many games on the market so I do not believe option agreements are totally out of the question. So if you’re a publisher maybe you could share your companies’ policy on this subject or if you have ever been in my situation. I would greatly appreciate any guidance.