Answer:
C. Aimee used the Associative and Commutative Properties to put numbers that are easy to add next to each other.
Explanation:
The given problem is

Aimee's first step is

As you can observe Aimee associated all numbers in a way that helped her to percieve clearl the operations she needs to do. That's a proper use of the associative property.
Therefore, the right answer is C., because Aimme used the associative and commutative properties to make it easier for her.