题干
—Would you mind taking the underground to the theatre tonight?
— .it will take less time than driving a car.
A：Certainly
B：You're welcome
C：you'd better not
D：Of course not
答案(点此获取答案解析）
D
≤a(x+y)对一切正数x、y恒成立，则正数a的最小值为（ ）