Hey I’m sorry but I do not know the answer.
Answer:
Option B
Step-by-step explanation:
Here we have to apply " combination and permutation. " It is given that the drama club had to choose three booths from a selection of 9, considering the possible ways to choose so. This is a perfect example of combination. In nCr, n corresponds to 9, respectively r corresponds to 3.

Hope that helps!
D
using the double - angle identity
cos (2A) = cos² A - sin² A = 2cos² A - 1 = 1 - 2sin² A
the right side = 1 - 2sin² (112.5° ) with A = 22.5°
hence 2A = 2 × 22.5° = 45°
thus cos 45° = 1 - 2sin² ( 22.5°)