How does pre$-$emphasis and de$-$emphasis affect the overall frequency response of an audio signal?

Question $1$ Answer

a$.$

The effect depends on the specific filter characteristics used.

b$.$

It introduces a gradual roll$-$off in the high frequencies during both pre$-$emphasis and de$-$emphasis.

c$.$

It boosts high frequencies during pre$-$emphasis and cuts them back during de$-$emphasis, resulting in a flat overall response.

d$.$

It has no significant impact on the overall frequency response.