$($c$)$ Examine the following convolution kernels, which can be used to remove some

noise from an image?

Convolution kernels:

$A=([1,1,1],[0,0,0],[-1,-1,-1]),B=([1,1,1],[1,1,1],[1,1,1])C=([-1,-1,-1],[-1,8,-1],[-1,1,-1]),D=([-1,-1,-1],[-1,9,-1],[-1,-1,-1])$

$[4$ marks$]$