A fundamental architectural principle in Salesforce Loyalty Management is that a single Loyalty Member Portal, which is an Experience Cloud site, can only be associated with one Loyalty Program. Therefore, to support a new Loyalty Program, a new portal must be created. To meet the requirement of retaining the same design and functionality, the most efficient approach is to build this new portal using the existing, pre-built Experience Cloud components, themes, and layouts from the original portal. This ensures a consistent member experience across both programs without redundant development effort.

A. A single Experience Cloud site (Loyalty Member Portal) cannot be assigned to more than one Loyalty Program at the same time.

C. Creating new components is unnecessary and inefficient, as the requirement is to replicate the existing design and functionality, which can be achieved with existing components.

1. Salesforce Help - Create a Loyalty Program: In the setup steps for a Loyalty Program, the "Experience Cloud Site" field is a lookup that allows associating only one site with the program. This demonstrates the one-to-one relationship. (See Step 6 under "Create a Loyalty Program").

2. Salesforce Help - Set Up Your Loyalty Program's Experience Cloud Site: This document outlines the process of creating a new site using the Loyalty Management template. It states, "After you create the site, you can associate the site with your loyalty program," confirming that a new program requires a dedicated site to be created and associated.

3. Salesforce Help - Loyalty Management Components in Experience Builder: This guide details the standard, reusable components available for building a Loyalty Member Portal, such as Loyalty Member Profile and Loyalty Tier Progress. This supports the concept of using existing components to build out the functionality of a new portal.