People will find themselves suffering from headache and watering eyes, and even snowhlindness, when______to several hours of "snow light".

A．being exposed

B．having been exposed

C．exposed

D．exposing

江户时代的杰作《回首美人图》的作者是谁？（）

A.歌川广重

B.菱川师宣

C.尾形光琳

D.葛饰北斋