(A) Decays as 1 / R, where R is the separation distance between the emitter and the receptor
(B) Decays as R, where R is the separation distance between the emitter and the receptor
(C) Decays as 1 / 2 R, where R is the separation distance between the emitter and the receptor
(D) Decays as 2R, where R is the separation distance between the emitter and the receptor

