A body is in pure rotation. The linear speed v of a particle on the body, the distance r of the particle from the axis and the angular velocity ω of the body are related as ω = V / r . Thus

Position of the particle on the body may change.So speed (v) and radial distance (r) of the particle may change.But ω does not depend upon the position of the particle .ω can only change if an external torque acts on the body.So option - (4) is right.