单选题：Given the structure of a binary search tree (as shown in the fig

Given the structure of a binary search tree (as shown in the figure), which one of the following insertion sequences is impossible? @[C](3)


A. `82 66 90 97 21 78`
B. `82 66 78 90 21 97`
C. `82 90 78 66 21 97`
D. `82 90 66 97 78 21`




A.`82 66 90 97 21 78`
B.`82 66 78 90 21 97`
C.`82 90 78 66 21 97`
D.`82 90 66 97 78 21`


答案：C