Gary and his friends go to see a movie. Gary buys x movie tickets at the rate of $8 per ticket and a tub of popcorn for $5.50.
If f(x) is the total amount he spends at the theater, which of the following linear functions models this situation?

A. f(x) = 8x + 5.50
B. f(x) = 5.50x + 8
C. f(x) = 44x
D. f(x) = 13.50x