A theater company charges $8.50 per ticket for people of all age groups. If c represents the total number of children who bought tickets and a represents the total number of adults who bought tickets, which expression best represents the total money earned by the company from the sale of tickets?
(5 points)
Group of answer choices
17(c + a)
c + 8.5a
8.5c + a
8.5(c + a)