The answer is 4. A function cannot have the same x value twice- 1 has two (2), 2 has all (1), 3 has two (-3), so 4 is the only answer.
Do you want the scientific notation?
If so, the answer would be 
First let's do $32.60 * 8 months = $260.80
Now add $40 from the down payment to $260.80
$260.80 + $40 = $300.80