A tire that is leaking air has an initial air pressure of 30 pounds per square inch (psi). The function t = f (p) models the amount of time t, in hours, it takes for the air pressure of the tire to reach p psi. What are the units for f'(p)? The table states

1, 2, 3, 4, 5, 6, t(hours)
25, 55, 92, 150, 210, 275 s(t) (miles)

Answer choices:
A.37
B.49
C. 58
D. 65
E. 92