已知三角形ABC所在平面α外一点P到三角形三边AB、BC、AC的距离相等，那么P点在平面α内的射影是△ABC的（　　）

A．外心

B．内心

C．重心

D．垂心

We usually accept payment by irrevocable L/C payable （） shipping documents.

A. among

B. between

C. about

D. against