Explanation

(c)
Given circumference of a circle $S = 2\pi R = 56$
$\Rightarrow \ \ \ \ \ R = \frac{28}{\pi}$
$\therefore\ \ \ Error\ \delta S = 2\pi\ \delta r = 0.02$
$\Rightarrow \ \ \ \ \delta r = \frac{0.02}{2\pi}$
Let area of circle , $A = \pi r^{2}$
$\therefore Percentage\ error\ in\ \ \ A = \frac{\delta A}{A} \times 100$
$\ \ \ \ \ = 2 \times \frac{\delta r}{r} \times 100$
=2$\times \frac{0.02 \times \pi}{2\pi \times 28} \times 100 = \frac{1}{14}$