You create a Web site with membership and personalization enabled. You must use an existing CRM database for storing the membership information. You need to implement the Membership Provider. What should you do?（）

• A、Modify the connection string in the Web.config file to connect to the CRM database.
• B、Add new a SqlMembershipProvider to the Web.config file.
• C、Create a custom Membership Provider inheriting from MembershipProvider.
• D、Create a custom MembershipUser inheriting from MembershipUser.