已知二叉树的前序遍历为[A,B,D,E,C,F,G],中序遍历[D,B,E,A,F,C,G],求二叉树的后序遍历的结果是( )
[D,E,B,F,G,C,A]
[D,E,B,FG,A,C]
[D,B,E,F,G,C,A]