冀州市白昼最长时（　　）

A．北极圈内出现极夜

B．北半球昼短夜长

C．阳光直射在北回归线上

D．南极圈内有极昼现象

If you want to try some of the most _____ skiing in the world, you should try a visit to Kitzbuel,

_____ in southern Austria. [ ]

A. challenged; located

B. challenging; locating

C. challenged; locating

D. challenging; located