C. because he owes money so his balance would be negative. He also owes less than 40 so the only possible choice would be D. because it is negative and less than -40.
First, you know that B is the mid point, meaning AB is equal to BC. Therefore, you can set up the equation: x+5=2x-11. Then, you solve for x. Once you are done solving, you should get 16. Hope this helps!