单选题：The following list is a series of operations for a stack:

The following list is a series of operations for a stack:
* push 1
* push 2
* pop
* push 3
* pop
* push 4
* push 5
* pop
* pop
* pop
* push 6
* push 7
* pop
* pop
* push 8
* pop
* push 9
* pop

Which is the correct pop-up sequence？
@[C](3)

A. 1 2 3 4 5 6 7 8 9
B. 9 8 7 6 5 4 3 2 1
C. 2 3 5 4 1 7 6 8 9
D. 2 3 5 4 7 6 8 9 1



A.1 2 3 4 5 6 7 8 9
B.9 8 7 6 5 4 3 2 1
C.2 3 5 4 1 7 6 8 9
D.2 3 5 4 7 6 8 9 1


答案：C