Solution:

When we divide a circle in to 4 equal parts the centre of the circle (360 degree) is also divides into 4 equal parts. Thus the above is a quarter of a circle.

And 8 is the radius of the circle.
Therefore, Area of the whole circle- \(πr^2\)=64π
To find the quarter of the circle, divide the area by 4=\(\frac{ 64π}{4}\)=16π

Now, we can find the area of the triangle= 32

Thus, the are of the shaded region= Area of the circle-Area of the triangle=16π-32

IMO B

Hope this helps!