Gina pumps 40 cubic inches of air per second into a balloon. The function below shows the total amount of air f(t) inside the balloon after t seconds. f(w) = 40t + 5

Which statement best describes the y-intercept of the graph of the function?
A) It is equal to 40 and represents the amount of air already present in the balloon before Gina starts blowing.
B) It is equal to 5 and represents the amount of air already present in the balloon before Gina starts blowing.
C) It is equal to 5 and represents the amount of air in the balloon after 1 second.
D) It is equal to 45 and represents the amount of air in the balloon after 1 second.