Which statement is true regarding the above query if one of the values generated by the sub query is NULL?

Evaluate the following SQL statement: SQL> SELECT cust_id. cust_last_name FROM
customers WHERE cust_credit_limit IN (select cust_credit_limit FROM customers WHERE
cust_city=’Singapore’): Which statement is true regarding the above query if one of the
values generated by the sub query is NULL?

A.
It produces an error.

B.
It executes but returns no rows.

C.
It generates output for NULL as well as the other values produced by the sub query.

D.
It ignores the NULL value and generates output for the other values produced by the sub
query.