单项选择题

A.二进制数有两个数码0和1
B.八进制数有八个数码0,1,2,3,4,5,6和7
C.十进制数有十个数码0,1,2,3,4,5,6,7,8,9
D.十六进制数有十六个数码0,1,2,3,4,5,6,7,8,9,10,12,12,13,14,15