Can I have a field that would allow me to set limits for each option and disable when the limit is reached?

Can i select a training course from a drop down box which then takes them to a select the date page and then this course once say 10 people have signed up it either say course fully booked or disapear from the options

We don't have this option in a dropdown field. We have the following widgets that would allow you to set a limit and automatically disable option when its limit is reached.

https://widgets.jotform.com/widget/appointment_slots 

https://widgets.jotform.com/widget/ticket_purchases

https://widgets.jotform.com/widget/gift_registry

https://widgets.jotform.com/widget/inventory 

Please follow the steps from this guide to add a widget in your form: https://www.jotform.com/help/252-How-to-Add-a-Widget-to-your-Form.