单项选择题

A.1/3-1/3-1/3或1/5-2/5-2/5
B.1/4-2/4-1/4或1/5-2/5-2/5
C.1/3-1/3-1/3或1/4-2/4-1/4
D.1/3-1/3-1/3或2/5-2/5-1/5