Respuesta :

c = 20 +15d because you already have to pay $15 plus $20 per day
Vowing

The answer is option 3. This is because it is showing the following: the total cost(c) is equal to(c=) $20 per day(c=20d) plus 15(c=20d+15)

The answer is option 3 (c=20d+15)