Final answer:
The valid use cases for declarative customization include displaying the number of employees on an opportunity page, determining a lead rating, and calculating the sales tax on a quote.
Step-by-step explanation:
The valid use cases for declarative customization are:
- Displaying the number of employees of the account related to an opportunity, on the opportunity page layout.
- Determining a lead rating, based on checking the value of 3 lead fields.
- Calculating the sales tax applicable to a quote, that is based on various factors such as product, state, quantity.
These use cases involve defining rules, conditions, and calculations that can be configured and executed without writing code.