What Is the Difference Between Diegetic and Nondiegetic Sound

What is the difference between diegetic and nondiegetic sound?

A) Diegetic sound is offscreen; nondiegetic sound can be on-screen or offscreen.
B) Diegetic sound provides no relevant spatial or temporal dimensions; nondiegetic sound provides an awareness of where the sound emanates.
C) Diegetic sound is recorded during postproduction; nondiegetic sound is recorded during production.
D) Diegetic sound originates from a source within a film's world; nondiegetic sound comes from outside that world.
E) Diegetic sound is assumed to be inaudible to the on-screen characters; nondiegetic sound accompanies action and speech depicted on-screen.