The Charleston bending brace is preferred over other braces because it:

1. is worn only 23 hours a day.
2. is worn for 8 to 10 hours at night.
3. is worn at night, when human growth hormone level is highest.
4. corrects any associated upper airway obstruction.
a. 1
b. 2
c. 2, 3
d. 1, 3, 4

C
The Charleston bending brace is worn for 8 to 10 hours at night, when a child's human growth hormone level is highest.