How does contact duplication work in SAP Emarsys Customer Engagement? Note: There are 2 correct Answer to this question.

How does contact duplication work in SAP Emarsys Customer Engagement? Note: There are 2 correct Answer to this question.
A . It runs once a day, checking against the full database.
B. Contacts with the same unique identifier are merged automatically on import.
C. Contacts with identical first name and last name are merged automatically.
D. It runs every time a new contact is about to be imported.

Answer: B,D