A stone tied to the end of a string of 1 m long is whirled in a horizontal circle with a constant speed. If the stone makes 22 revolution in 44 seconds, what is the magnitude and direction of acceleration of the stone-

Question

( A ) $\pi^2ms^-2$ and direction along the radius towards the centre.
( B ) $\pi^2ms^-2$ and direction along the tangent to the circle.
( C ) $\pi^2ms^-2$and direction along the radius away from the centre. .
( D ) $\frac{\pi^2}4{ms^-2}$ and direction along the radius towards the centre.