—Hi，Jack！I'm glad I came across you here.

—________，Alice?

A．Who is that speaking

B．How about another cup of tea

C．Why？What's up

D．What can I do for you

电动机外壳保护线，对于TN－C系统应与（）相连，对于TN－S系统，应将电动机外壳与（）相连。

A、N线

B、PE线

C、PEN线