A. The need to maintain the Account_share object based upon the Custom Account Team object data.
When creating custom functionality that mimics or extends Salesforce's standard sharing features (such as Account Teams), it's crucial to programmatically manage sharing entries to ensure that users have the correct access to Account records. This involves creating, updating, or deleting records in the AccountShare object to reflect the sharing access defined by the Custom Account Team object. Apex sharing is necessary to manually maintain sharing entries when using custom objects for sharing purposes.

D. The need to synchronize the AccountTeamMember object with the Custom Account Team object data.
Although the question suggests moving away from the standard Account Team functionality, there could be a scenario where some level of synchronization between the new Custom Account Team object and the standard AccountTeamMember object is desirable. This could be for backward compatibility, reporting purposes, or to maintain some native Salesforce functionality that depends on the standard Account Team structure. However, if the move to a custom object is meant to completely replace the standard functionality, the focus would be more on ensuring that all necessary features are replicated or enhanced in the custom implementation, potentially making this synchronization less relevant....

A. The need to maintain the Account_share object based upon the Custom Account Team object data.
Creating a Custom Account Team object means that sharing settings which were automatically managed by Salesforce's standard Account Team functionality will now need to be manually maintained. This involves programmatically creating and updating share records on the Account object (using the AccountShare object in Apex) based on the relationships defined in the Custom Account Team object. This approach is essential for ensuring that access permissions are correctly replicated from the custom implementation to the actual Account records in Salesforce, mirroring the sharing behavior of the standard Account Team functionality.

B. The need to customize Account screens in Visualforce, as the Account_share object cannot be maintained programmatically.
While the first part of the statement is accurate in terms of the potential need for customization, the reason provided is not accurate—AccountShare objects can indeed be maintained programmatically, which is central to custom sharing logic. However, customizing Account screens in Visualforce may be necessary to properly incorporate and display the new Custom Account Team related information, controls, or any additional functionality that goes beyond what standard layout customization allows. This ensures that users can interact with the new Custom Account Team data and functionalities directly from the Account screens, offering a seamless user experience that integrates the custom enhancements effectively....