Consider the decision tree for insertion sort. For each of the following, state an answer. No justification.

$($a$)$

At what level would we find the shallowest leaf? $($Use big$-$O notation$)$

$($b$)$

At what level would we find the deepest leaf? $($Use big$-$O notation$)$

$($c$)$ How many leaves are there overall?

$($No big$-$O$)$