$($Classifcation$)$ Corsider the following figures $($A$),($B$),($C$)$ and $($D$)$ of different shape plotted in a two

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

$($a$)(2$ pt$)$ Which figure best illustr ate the substantial class imbalanoe? Briefly explain your answer.

$($b$)(2$ pt$)$ Which figure is linearly separable? That is$,$ can you draw a straight line to separate the categories?

Briefly explain your arswer.

$($c$)(2$ pt$)$ Which figure correponds to a rmulti$-$clacs classification problem? Briefly explain your answer.

$($d$)(4$ pts$)$ Suppose we apply the following feature transformation where $(x_1<mn\; id="EditorElement\_487705">0</mn>$

and $x_2>0)$ is a boolean expression where if the expresion is true, we use value $1$ and if the expression is

false, we use the value $0.$ Which of the above plots is linearly separable and why?

The questions are below in the image.