Suppose the price of admission to the state fair is $9.50, and each ride costs an additional $2.25. Karen is going to the state fair. If she can spend at most $50, which inequality can be used to solve for r, the number of rides Karen can go on?

A) 9.50 + 2.25r ≥ 50
B) 9.50r + 2.25 ≥ 50
C) 9.50 + 2.25r ≤ 50
D) 9.50r + 2.25 ≤ 50