JEE Math Practice Question

The maximum distance from origin of a point on the curve $$x = a\sin t - b\sin \left( {{{at} \over b}} \right)$$ $$y = a\cos t - b\cos \left( {{{at} \over b}} \right),$$ both $$a,b > 0$$ is

1. A.$$a-b$$
2. B.$$a+b$$
3. C.$$\sqrt {{a^2} + {b^2}} $$
4. D.$$\sqrt {{a^2} - {b^2}} $$