单选题：Insert { 28, 12, 18, 36, 42, 30 } one by one into an initially e

Insert { 28, 12, 18, 36, 42, 30 } one by one into an initially empty AVL tree. The pre-order traversal sequence of the resulting tree is: @[C](2)

A. 36, 18, 12, 30, 28, 42
B. 12, 18, 30, 42, 36, 28
C. 28, 18, 12, 36, 30, 42
D. 28, 12, 18, 36, 30, 42



A.36, 18, 12, 30, 28, 42
B.12, 18, 30, 42, 36, 28
C.28, 18, 12, 36, 30, 42
D.28, 12, 18, 36, 30, 42


答案：C