Can I limit one option within a survey?

Within a survey, we want the first 50 people to get a t-shirt but after that we want the option to close. Is this something we could achieve and if so how? 

You can disable the form when you reach 50 submissions in the Form Status page. To do that, please follow this guide:

1. Open your form in the Form Builder.
2. Go to the Settings page.
3. Select the Form Settings tab.
4. Change the Form Status to Disable on submission limit.

I hope this helps.