View the exhibit and examine the ORDERS table. 

The ORDERS table contains data and all orders have been assigned a customer ID. Which statement would add a NOT NULL constraint to the CUSTOMER_ID column? 

Answer options:

A. ALTER TABLE orders MODIFY CONSTRAINT orders_cust_id_nn NOT NULL (customer_id);
B. ALTER TABLE orders ADD CONSTRAINT orders_cust_id_nn NOT NULL (customer_id);
C. ALTER TABLE orders MODIFY customer_id CONSTRAINT orders_cust_nn NOT NULL (customer_id);
D. ALTER TABLE orders ADD customer_id NUMBER(6)CONSTRAINT orders_cust_id_nn NOT NULL;

C