结点所拥有的子树的个数称为该结点的度，树中所有结点的最大层数称为树的 。

给出一棵树的逻辑结构T=(N,R),其中： N={A,B,C,D,E,F,G,H,I,J,K} R={r} r={(A,B),(B,E),(B,F),(F,G),(F,H),(A,C),(C,I),(C,J),(J,K),(A,D)} 试回答下列问题： Given a logical structure of a tree, T=(N, R), and N={A, B, C, D, E, F, G, H, I, J, K}, R={r}, r={(A,B), (B,E), (B,F), (F,G), (F,H), (A,C), (C,I), (C,J), (J,K), (A,D)} Please answer these questions: （1）哪个是F的父结点？which is the parent node of Node F? （2）哪些是B的子孙？which are the offspring of Node B? （3）以结点C为根的子树的深度是多少？what is the depth of the sub-tree whose root node is Node C? （注：根的层数为0，独根树深度为0，高度为1，其他题目同样如此；各个选项之间的答案用空格分隔就好；同一个选项的答案如果有多个字母，按照字典序排列，且不要以空格分隔） （P.S. the level of the root node is 0, the depth of a tree, which only has a root node, is 0, and its height is 1. Other problems have the same regulations. If there are several alphabets in one question, order them by lexicographical order, and do not add spaces.)

邻接阵矩可以看出，该图共有几个顶点? ( )

A、9

B、3

C、6

D、1

邻接阵矩可以看出，如果是有向图，该图共有几条弧？( )

A、5

B、4

C、3

D、2