已知m、n是关于x的一元二次方程x²+2ax+a²+4a-2=0的两实根，那么m²+n²的最小值是______．

— Betty, you don’t look well. What's wrong?

—I have a fever.

— ______. You'd better go to see a doctor.

A．I'm sorry to hear that

B．Oh, mine

C．It's all right

D．You look bad