Final answer:
The cost function that Dylan could use to calculate how much he would charge a customer for 'h' hours of cleaning service would be c = 20 + 17.50h.
Step-by-step explanation:
To calculate the cost, Dylan charges a $20 fee plus $17.50 per hour. Let's represent the cost as 'c' and the number of hours as 'h'. So, the cost function would be c = 20 + 17.50h (option B). The $20 fee is a fixed cost, while the $17.50 per hour is the variable cost based on the number of hours.