A Charge Q Accumulates on the Hollow Metallic Dome,of Radius

A charge Q accumulates on the hollow metallic dome,of radius R,of a Van de Graaff generator.A probe measures the electric field strength at various points outside the sphere surface.By what factor will the electric field value at the 2R distance be changed if the charge value were increased to (9/4) Q?

A) (9/4) ²
B) 9/4
C) 4/9
D) (4/9) ²
E) ​9