To determine the change in Devon's account each month after paying for internet service, we should start by calculating the monthly payment amount.
Devon made a total payment of $936 over 8 months. To find the monthly payment, we can divide the total amount by the number of months:
\[ \text{Monthly Payment} = \frac{936}{8} = 117 \]
This means Devon paid $117 each month for internet service.
The change in Devon's account after this payment would typically be a negative amount because it represents money going out of his account. Therefore, if we are considering the change in his balance after the payment, it would be:
\[ \text{Change in Account Each Month} = -117 \]
However, your answer choices seem to list $-117 as separate options. The most appropriate response to indicate the change in Devon's account each month after paying for the internet service is:
-$117.