For a seamless integration between Marketing Cloud Account Engagement and a Salesforce custom object, two foundational requirements must be met. First, the custom object in Salesforce must be linked to a core prospect record (Lead, Contact, or Account) via a lookup or master-detail relationship. This association is critical for Account Engagement to relate the custom object's data to a specific prospect. Second, the Salesforce Connector User, which acts as the integration agent, requires at least 'Read' permission to the custom object and its fields. Without this permission, Account Engagement cannot access or sync the data from Salesforce.

C. A relationship to a Campaign or Opportunity is not a prerequisite for linking the custom object to a prospect for syncing purposes.

D. 'Display in Table' is a user interface configuration setting within Account Engagement, configured after the integration is established, not a foundational requirement for the integration itself.

1. Salesforce Help Documentation, "Considerations for Using Custom Objects":

This document explicitly states the prerequisites. Under the "Prerequisites" section, it lists: "To use custom objects with Account Engagement, they must have a relationship with a contact, account, or lead record." This directly supports option A.

The same section also states: "The connector user must have read permission for the custom object." This directly supports option B.

2. Salesforce Help Documentation, "Integrate Custom Objects":

This step-by-step guide reinforces the requirements. Step 1 is: "In Salesforce, create a custom object and associate it with the account, contact, or lead object." (Supports A).

Step 2 is: "Give the connector user read permission to the new object." (Supports B).

Step 5, "Map fields," includes the action to "Choose which fields to display in the Account Engagement table," confirming that this is a later configuration step, not a prerequisite for integration. (Refutes D).