已知选修课学生名单 course1 = {"张三", "李四", "王五"}, course2 = {"李四", "赵六", "王五"}。要找出同时选修两门课的学生，应使用的推导式是？（ ）
{x for x in course1 if x in course2}
[x for x in course1 and course2]
{x for x in course1 or course2}
{x for x in course1 if x not in course2}