A table SALES has four attributes (cust_Id, order_Id, product_code, product_count). Which of the following is the composite key? O A. {cust_id, product_code) O B.{order_id} O c. {cust_id] O D. {product_code} What is the type of subclass constraint that one entity can be a member of at most one subclass is called O A. Disjointness constraint O B. Jointness constraint O C. Incomplete joint constraint OD. Complete joint constraint What is the correct approach for E-R modeling technique? O A. Left-right approach OB. Bottom-up approach C. None of the above O D. Top-down approach Which of the following is FALSE about the job responsibilities of the database administrator? O A. Diagnose and troubleshoot database errors O B. Install and maintain the performance of database servers O C. Understanding of relational and dimensional data modeling O D. Develop processes for optimizing database security