单选题：A B+ tree of order 3 with 21 numbers has at least ___ nodes of d

A B+ tree of order 3 with 21 numbers has at least ___ nodes of degree 2. @[A](3)

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



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


答案：A