单选题：After inserting 7 into the 2-3 tree given in the figure, how man

After inserting 7 into the 2-3 tree given in the figure, how many of the following statements are TRUE? @[C](2)

(S1) The root still contains 9 only;

(S2) the tree grows higher;

(S3) 4 and 9 are in the same nonleaf node;

(S4) the interior node containing 12 keeps unchanged.

A. 0
B. 1
C. 2
D. 3






A.0
B.1
C.2
D.3


答案：C