Final answer:
A smaller round brush provides more volume and body to the hair during air forming.
Step-by-step explanation:
The correct answer is B) It provides more volume and body to the hair. When air forming, a smaller round brush is used to create more volume and body in the hair. This is because the smaller brush creates more tension and lift at the roots, resulting in a fuller look. The smaller brush is also easier to maneuver, allowing for more control and precision when styling.