What Is the Advantage of Having Grape-Like Clusters Called Alveoli

What is the advantage of having grape-like clusters called alveoli as part of the respiratory system?

A) Alveoli allow for an increase in surface area, which maximizes gas exchange.
B) Alveoli are circular in structure, which is ideal for maximal gas exchange.
C) Because alveoli have thinner walls, gas exchange in the lungs is facilitated.
D) The grape-like shape of alveoli allows capillaries to be in closer proximity to gases.