To solve this problem, we will compute the total amount Helen paid back and we will subtract $2,500 from it.
To determine the total amount she paid back we multiply the number of payments by the amount of each payment:
[tex]T=24\times115\text{dollars}=2760\text{ dollars.}[/tex]Subtracting $2,500 from the above result we get:
[tex]2760-2500=260\text{dollars.}[/tex]Answer: Option d.