Question $33(3$ points$)$

When inserting $4$ data records with the following key values $($with the order given$)$

into an empty AVL tree, which of the following is correct?

key values: $30,15,40,35$

double rotation is needed with right rotation at $30$ and left rotation at $35$

double rotation is needed with left rotation at $30$ and right rotation at $40$

a single left rotation is needed at node $30$

a single right rotation is needed at node $40$

no rotation is needed