The correct answer is:

C. Create one Visualforce Page for use by both profiles.

To enforce Field Level Security and keep future maintenance to a minimum, the developer should create a single Visualforce page. Visualforce pages respect the field-level security settings defined in the Salesforce setup, so the page will automatically hide the `Customer_Satisfaction__c` field for support reps while displaying it for support managers. This approach simplifies maintenance by ensuring that changes to the page only need to be made once and not duplicated across multiple versions.