Which of the Following SQL Statements Is a Correctly Stated

Which of the following SQL statements is a correctly stated correlated subquery?

A) SELECT C1.CustName,C1.SalesRepNo
FROM CUSTOMER C1
WHERE C1.SalesRepNo IN
(SELECT S1.SalesRepNo
FROM SALESREP S1
WHERE S1.RepName = 'Smith') ;
B) SELECT C1.CustName,C1.SalesRepNo
FROM CUSTOMER C1
WHERE C1.SalesRepNo IN
(SELECT S1.SaleRepNo
FROM SALESREP S1
WHERE S1.RepName = 'Smith')
AND C1.SalesRepNo=S1.SalesRepNo) ;
C) SELECT C1.CustName,C1.SalesRepNo
FROM CUSTOMER C1
WHERE C1.SalesRepNo IN
(SELECT S1.SaleRepNo
FROM SALESREP S1
WHERE S1.RepName = 'Smith')
AND C1.SalesRepNo<>S1.SalesRepNo) ;
D) SELECT C1.CustName,C1.SalesRepNo
FROM CUSTOMER C1
WHERE C1.SalesRepNo IN
(SELECT C2.SaleRepNo
FROM CUSTOMER C2
WHERE C1.SalesRepNo=C2.SalesRepNo) ;
AND C1.OrderNo<>C2.OrderNo) ;