What should the Architect do to ensure Field-Level Security is enforced on a custom Visualforce page using the Standard Lead Controller?

the Architect should use {!$FieldType. lead. accessible} expression within the Visualforce page.

Explanation:

Visualforce is a framework that allows developers to build complex, user friendly interfaces that can be hosted primarily on the Lightning Platform

Controllers provide access to the data that should be displayed in a page, and can modify component behavior. a number of standard controllers are provided by The Lightning platform that contain functionality and logic that which are used for standard Salesforce pages

The Architect should Use the expression {!$FieldType. lead. accessible} within the Visualforce page.