Answer:
B
Step-by-step explanation:
The contractor gets $75 for every single customer she sets up. Okay, so if she sets up 1 customer, she gets $75, if she sets up 2, she gets $150 and so on.
This is a multiplication expression since multiplication is just repeated addition, which is what is happening in this case, where the contractor gets $75 added to her account every time she sets another person up.
At this point you can just eliminate the other answer options except for B, so it is B.
But to double check... if you multiply 75 by 8, you would get $600, which is B.