Exercise I $(35$ points$)$

Suppose that we have numbers between $1$ and $1200$ in a binary search tree $($BST$),$ and we want to search for the

number $400.$ Which of the following sequences could not be the sequence of nodes examined on a BST$?($Recall Grading

Guidelines. I suggest to use tree drawing to justify your answer. Drawing is strongly advised to make explanations easier

to follow for you and your grader. Justify only for the sequence$($s$)$ that could not be the sequence of nodes examined.$)$

a$.102,499,489,321,368,484,483,405,501.$

b$.1062,405,474,718,426,519,465,501.$

c$.1052,329,1139,367,1039,383,501.$

d$.140,390,539,536,468,482,435,501.$

e$.1062,358,1049,382,1036,396,500,501.$