Locus of centroid of the triangle whose vertices are (a cos t,a sin t), (b sin t,-b cos t) and (1,0), where t is a parameter, is A)(3x-1)2+(3y)2=a2-b2 B)(3x-1)2+ (3y)2=a2+b2 C) (3x+1)2+ (3y)2=a2+b2 D) (3x+1)2+ (3y)2=a2-b2 Here 2 is read as square