The CUSTOMERS table has these columns: Which statement

单项选择题

The CUSTOMERS table has these columns:

Which statement finds the rows in the CUSTOMERS table that do not have a postal code?（）

A. SELECT customer_id, customer_name   FROM customers   WHERE postal_code CONTAINS NULL;
B. SELECT customer_id, customer_name   FROM customers   WHERE postal_code = '________';
C. SELECT customer_id, customer_name   FROM customers   WHERE postal_code IS NULL;
D. SELECT customer_id, customer_name   FROM customers   WHERE postal code IS NVL;
E. SELECT customer_id, customer_name   FROM customers   WHERE postal_code = NULL;

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