A Uniform Circular Ring Has Charge Q and Radius R

Multiple Choice

A uniform circular ring has charge Q and radius r.The magnitude of the electric field at a distance of r along the axis of the ring is E_o.If the radius were to double,then calculate the new electric field at a distance of r along the axis of the ring in terms of E_o.

A) 0.40 E_o
B) 0.25 E_o
C) 0.50 E_o
D) 0.20 E_o
E) 0.089 E_o