28 利用由左而右順序的數字資料：7, 34, 17, 19, 16, 10, 23, 2，來建立二元搜尋樹（binary search tree）。若是用後序追蹤（postorder traversal）此樹，其輸出為何？
(A)2, 10, 16, 23, 19, 17, 34, 7
(B)7, 2, 34, 17, 16, 10, 19, 23
(C)2, 7, 10, 16, 17, 19, 23, 34
(D)2, 7, 17, 16, 10, 19, 23, 34代號：5438頁次：4－4