The owner of the theater where the ticket price for an adult is $10 and the ticket price for a child is $7 wants to make at least $300 when a movie is shown. Choose the inequality that shows the numbers of tickets that must be sold.
A. 10x + 7y > 300
B. 10x + 7y < 300
C. 10x + 7y ≥ 300
D. 10x + 7y ≤ 300