Which of the following is a valid SELECT statement?
a. SELECT order# FROM orders

WHERE shipdate = SELECT shipdate FROM orders
WHERE order# = 1010;

b. SELECT order# FROM orders

WHERE shipdate = (SELECT shipdate FROM orders)
AND order# = 1010;

c. SELECT order# FROM orders

WHERE shipdate = (SELECT shipdate FROM orders
WHERE order# = 1010);

d. SELECT order# FROM orders

HAVING shipdate = (SELECT shipdate FROM orders
WHERE order# = 1010);