7 已知某二元樹(Binary Tree)的拜訪序列如下: 前序(Pre-order):[8, 10, 9, 1, 3, 7, 12, 6] 中序(In-order):[10, 9, 1, 8, 12, 7, 3, 6] 試問該二元樹正確的後序(Post-order)拜訪序列為何? (A)[10, 9, 1, 12, 7, 6, 3, 8] (B)[6, 3, 7, 12, 1, 9, 10, 8] (C)[1, 9, 10, 6, 3, 7, 12, 8] (D)[1, 9, 10, 12, 7, 6, 3, 8]