Your company uses a SQL Server 2005 database. Customer data from your trading partners is imported into the Customers table every night. You need to ensure that the customer record is updated if it already exists in the Customers table. If the record does not exist, the data needs to be inserted into the Customers table. What should you do?（）

A. Create a FOR trigger.
B. Create an INSTEAD OF trigger.
Create an AFTER trigger.
D. Create a DDL trigger.