The graph shows the total number of participants in a town's recreation program at the end of every year since the year 2000. The line of best fit for the data is given by the equation =13+50, where y is the total number of participants x years after the beginning of the year 2000. Which statement correctly interprets the slope of the line of best fit?

A. The rate of change is 1 new participant every 13 years.

B. The rate of change is 13 new participants every 13 years.

C. The rate of change is 13 new participants every year.

D. The rate of change is 50 new participants every year.