Why do we focus on pressure waves more than displacement waves in this experiment?$$

Question $5$ options:

a$)$ because pressure waves are much more common than displacement waves in Nature.

b$)$ because pressure waves can make music, but displacement waves can$$t$.$

c$)$ because we can measure the pressure waves but not the displacement waves in this experiment.

d$)$ because displacement waves don$$t really exist, but pressure waves do$.$