With Regard to Sound, What Is the Crucial Difference Between

With regard to sound, what is the crucial difference between sound and silent films?

A) A sound film can emphasize silence, but a silent film has no option.
B) A sound film only uses diegetic sound, but a silent film can use nondiegetic sound.
C) A sound film uses automatic dialogue replacement (ADR) , but a silent film uses rerecording.
D) A sound film does not use ambient noise, and silent films only use sound effects.
E) A sound film's fidelity is never faithful to its source, and silent films are always faithful to their sources.