$($Classification$)$ Consider the following figures $($A$),($B$),($C$)$ and $($D$)$ of different shapes plotted in a two

dimensional feature space $(x_1,x_2).$ Suppose we are interested in classifying the type of shape.

$($A$)$

$($B$)$

$($C$)$

$($D$)$

$($a$)(2pt)$ Which figure best illustrate the substantial class imbalance? Briefly explain your answer.