Sarah has been training for a swim meet. Her one-mile swim times for each training session are in the table Session Time 1 40.0
2 39.2
3 38.4
4 37.6

Which type of function best models Sarah’s swim time and why?
A.
a linear function, because the time is decreasing at a constant rate per session

B.
a linear function, because the time is decreasing at a constant percent rate per session

C.
an exponential function, because the time is decreasing at a constant rate per session

D.
an exponential function, because the time is decreasing at a constant percent rate per session