Answer:
Step-by-step explanation:
Actually, none of these represent direct proportion, because each one involves adding or subtracting an offset.
The last answer is closest to being a proportional relationship:
$1.75 per pound → Total cost = ($1.75/lb)x, where x is the number of pounds. This line would go through the origin, as it must, for the relationship to be proportional. But as soon as we add in or subtract that $1 coupon, this is no longer a proportional relationship.