Consider the following B$+$ tree $($partly shown$)$ defined on an attribute with an integer domain in a relation $r.$ Leaf nodes are linked $($the links are not shown in the figure$).$ The nodes are annotated with a label $($e$.$g$.,"$L$1"$ for leaf node $1,"$I$2"$ for intermediate node $2).$ Answer the following questions.

$($a$)$ The B$+$ tree nas at most $4$ search keys in its node. wnat's the degree of the tree?

$($b$)$ Consider the subtree A$.$ Give the permissible ranges of the search keys in A$\text{'}$s nodes.

$($c$)$ Give the labels of all the nodes that need to be visited to answer the query: ${}_{a}96(r)$

$($d$)$ Answer the same question, but for the query: "find the records with search keys in $[56,96)".$

$($e$)$ Subtree C is not shown. What can we infer about the contents and shape of this subtree?