Exam CRT-450 topic 1 question 291 discussion

When you have duplicate lead, contact, case, or account records in the database, cleaning up your data and consolidating the records might be a good idea. You can merge up to three records of the same sObject type. The merge operation merges up to three records into one of the records, deletes the others, and reparents any related records.

Merge Considerations When merging sObject records, consider the following rules and guidelines: Only leads, contacts, cases, and accounts can be merged. See sObjects That Don’t Support DML Operations. You can pass a master record and up to two additional sObject records to a single merge method. Using the Apex merge operation, field values on the master record always supersede the corresponding field values on the records to be merged. To preserve a merged record field value, simply set this field value on the master sObject before performing the merge. External ID fields can’t be used with merge. For more information on merging leads, contacts and accounts, see the Salesforce online help. from salesforce so AB

B is incorrect, as merge is also supported with other standard and custom objects, not just accounts, contacts, cases, and leads. Statement C is also incorrect, as external ID fields cannot be used with the merge method.