设有如下创建b_room表的语句: CREATE TABLE tb_room( rno CHAR(10)NOTNULL, rtype CHAR(20)NOT NULL, rprice INT NULL, rmemo CHAR(50)NULL); 以下语句中,能够正确实现将编号(rno)为r100的房间价格(rprice)由150180元的是()。 A. UPDATE tb room SET rprice=180 WHERE rno='r100'; B. UPDATE tb room SET rprice=180 WHERE rprice=150; C. UPDATE tb_room CHANGE rprice=180 WHERE rno='r100'; D. UPDATE tb_room SET rprice='180' WHERE rprice='150';