Answer : (d) 11: 12
Area of C = πr2, where P0B = r is the radius of the circle C.
Then radius of circle C1 = r/4
radius of circle C2 = r/8 and so on.
∴ Area of shaded portion = Area of C1 + Area of C2 + ........
= \(\frac{\pi r^2}{16}\) + \(\frac{\pi r^2}{64}\) + ...
= πr2 [ \(\frac{1}{16}\)+ \(\frac{1}{64}\)+ ... ]
= 11: 12