Answer:
A
Step-by-step explanation:
LCD stands for least common denominator. This means we must find the smallest denominater that is a factor of both 9 and 12.
Let's test all the answer choices:
Answer A:
36 is a factor of 9 and 12.
Answer B:
108 is a factor of 9 and 12.
Answer C:
72 is a factor of 9 and 12.
Now, which is the least.
36<72<108
So, the answer is 36 (A).
