Which SQL statement will accomplish the task?

View the Exhibit and examine the description for the CUSTOMERS table.

You want to update the CUST_CREDIT_LIMIT column to NULL for all the customers, where
CUST_INCOME_LEVEL has NULL in the CUSTOMERS table. Which SQL statement will
accomplish the task?

A.
UPDATE customers
SET cust_credit_limit = NULL
WHERE CUST_INCOME_LEVEL = NULL;

B.
UPDATE customers
SET cust_credit_limit = NULL
WHERE cust_income_level IS NULL;

C.
UPDATE customers
SET cust_credit_limit = TO_NUMBER(NULL)
WHERE cust_income_level = TO_NUMBER(NULL);

D.
UPDATE customers
SET cust_credit_limit = TO_NUMBER(‘ ‘,9999)
WHERE cust_income_level IS NULL;