Answer:
Option D. 8 units
Step-by-step explanation:
step 1
Find the area of rectangle
The area of rectangle is

step 2
Find the length side of the square with the same area of rectangle
The area of a square is

where
b is the length side of the square
we have

substitute

take the square root both sides

therefore
The length side of the square is 8 units
120/1500=x/100, x=8
So, you make 8% commision, meaning you now have to do this:
x/1300=8/100, so x=$104