单项选择题

下列程序段的结果为
A = "ABBACDDCBA"
For i=6 To 2 Step -2
X = Mid(A,i,i)
Y=Left(A,i)
Z=Right (A,i)
Z=X & Y & Z
Next
Print Z

A.ABC
B.AABAAB
C.BBABBA
D.ABBABA