单选题：Insertion of B+ Tree
To perform Insert on a B+ tree of order M, a node with M+1 keys will be split into 2 nodes.
After inserting $$1, 2, 3, ... , 9, 10$$ consequentially into an initially empty B+ tree of order 3, how many split operations have occurred in total?
A.2
B.3
C.4
D.5
答案：D
After inserting $$1, 2, 3, ... , 9, 10$$ consequentially into an initially empty B+ tree of order 3, how many split operations have occurred in total?
A.2
B.3
C.4
D.5
答案：D