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 { 2, 1, 6, 5, 3, 4 }, pre-order traversal sequence is { 4, 6, 1, 2, 3, 5 }, and in-order traversal sequence is { 1, ?, ?, 4, ?, 5 }, then the 3 missing numbers must be:



A.2, 6, 3
B.6, 2, 3
C.6, 3, 2
D.cannot be determined


答案：A