现有订单表orders，包含用户信息userid, 产品信息 productid, 以下（）语句能够返回至少被订购过两回的productid?

A.select productid from orders where count(productid)>1

B.select productid from orders where max(productid)>1

C.select productid from orders where having count(productid)>1 group by productid

D. select productid from orders group by productid having count(productid)>1

E.