49. 以下是比較二個二元樹是否相似(即樹的結構相同)的演算法，則空格中需填入：(A)Similar is (T1=T2) (B)Similar is Similar(T1，T2) AND Similar(T2，T1) (C)Similar is Similar(T1，T2) OR Similar(T2，T1) (D)Similar is Similar(T1^.Left，T2^.Left) AND Similar(T1^.Right，T2^.Right)