To go down in pitch means to . *

vibrate slowly and give a lower pitch.

Explanation: Sounds are higher or lower in pitch according to the frequency of vibration of the sound waves producing them.

Hope this helps sorry if it doesn't

a. symbolism

b. opinions

all of them

c. hidden messages

d. political statements

the answer is counterpoint.

counterpoint definition: "the art or technique of playing a melody or melodies in conjunction with another, according to fixed rules."

counterpoint is present in a lot of baroque music- such as bach (notably his wtc prelude and fugues) and scarlatti, but can also be found in music by mozart, beethoven. it can even be found in music as modern as john williams!