Help, please! :( The line graph shows tuition amounts for a university for the years 1996 through 1999. Which of the following is a valid claim based on the graph?

(A): The greatest one-year increase in tuition occurred from 1997 to 1998.
(B): The rate of increase was the same from year to year.
(C): Tuition rates doubled between 1996 and 1999.
(D): Tuition rates will continue to increase over the next 5 years.