单选题：For a given binary tree, if its post-order traversal sequence is

For a given binary tree, if its post-order traversal sequence is { 5, 2, 6, 4, 1, 7, 3 }, pre-order traversal sequence is { 3, 1, 5, 4, 2, 6, 7 }, then its in-order traversal sequence must be:



A.cannot be determined
B.5, 1, 2, 4, 6, 3, 7
C.2, 5, 6, 1, 4, 3, 7
D.1, 5, 4, 2, 6, 3, 7


答案：B