在学生关系student(sid,sname……)中,student的属性分别表示学号和姓名,若要查询学号为19170201的学生姓名,下列SQL语句正确的是( )。Ⅰ.SELECT sname FROM student WHERE sid LIKE '19170201'Ⅱ.SELECT sname FROM student WHERE sid LIKE= '19170201'Ⅲ.SELECT sname FROM student WHERE sid='19170201' A: Ⅰ、Ⅱ B: Ⅰ、Ⅲ C: Ⅱ、Ⅲ D: Ⅰ、Ⅱ、Ⅲ