Is it possible to present a Combo Box to the user, then reference the resulting selection within a business rule?

Answer

Yes, the first step will be to create the desired parameter to display the user choices. In this example, we are presenting a list of Scenarios to select from:

 

Next, you need to create a Combo Box component that is bound to the parameter:

 

In your business rule, you would reference the Parameter value as shown:

 

Source: Office Hours 2020-09-27 Partner Enablement