PLEASE HELP ASAP Camille is saving for a laptop that costs about $850. To model her savings plan and determine how many more months it will take her to reach her goal, she recently created this equation, where y represents the total amount saved and x represents the number of months. Which statement about her work is true?'

A. Camille used the associative property in step 3.

B. Camille used the multiplication property of equality in step 4.

C. Camille used the subtraction property of equality in step 5.

D. Camille used the substitution property in step 6.