To effectively bridge the gap between digital interactions and physical transactions in a multi-channel retail environment, Adobe Real-Time CDP utilizes specificIdentity Namespacesto create a cohesiveIdentity Graph.

Experience Cloud ID (ECID), formerly known as MCID, is the primary namespace used for tracking online behavior. It is automatically generated by the Adobe Experience Platform Web and Mobile SDKs to identify unique visitors across a company's web properties and apps. By using ECID, the architect can capture anonymous or pseudonymous behavioral data such as product views and cart additions.

For offline transactions (e.g., in-store purchases) and cross-channel linking, a PII-based identifier is required.Email_sha256is the industry-standard namespace for this purpose. When a customer provides an email at a physical point-of-sale (POS) or during an online checkout, hashing that email (using the SHA-256 algorithm) allows the business to safely store and match identities without exposing plain-text sensitive data. In theReal-Time Customer Profile, the Identity Service acts as the "glue"; it recognizes when a transaction containing an email_sha256 value belongs to the same individual associated with a specific ECID from a web session.

Option D is redundant as MCID is the legacy term for ECID. Option C (Device_ID) is typically too granular for general cross-channel transaction modeling. By combining ECID and Email_sha256, the architect ensures that online browsing behavior is stitched to offline purchase history, enabling high-value use cases like "online-to-offline" attribution and personalized re-engagement.