The function f(x) = 1.50x + 12.50 relates how much Kelsey pays for digital service, f(x), to the number of movies, x, she streams in a month. What is the value and meaning of f(18)? $27.00; this is the amount Kelsey pays for 18 months of service $27.00; this is the amount Kelsey pays for 18 movies in 1 month $39.50; this is the amount Kelsey pays for 18 months of service $39.50; this is the amount Kelsey pays for 18 movies in 1 month