The answer here is a, my reasoning because the money raised is the independent becuase they are charging 10$ per car no more no less for anyone, so then you look for the dependent variable which is the number of cars , since they dont know how much they will make exactly it could range and because of this uncertainty this becomes our dependent, so the domain is all we have left but the domain is the income or ammout of money you will make not the number of cars or the money raised hope this helped you have an amazing day!!
