Does this graph represent a function? Why or why not?

Which of the following best describes the figure?

Including 6% sales tax, an inn charges $135.68 per night. find the inns nightly cost

Which of the following best describes the graph below? + + 2 + 3 + 4 1 o a. it is not a function. o b. it is a one-to-one function. o c. it is a many-to-one function. o d. it is a function, but it is not one-to-one.