Puzzle of the Week #438 - parkrun Density

I have 17 parkruns within 17 miles from my house.

Assuming the density is broadly uniform, if I calculate the same stat but in kilometres, such that I have n parkruns within an n kilometre radius, what is a good estimate for n?

(There are ~1.61km in a mile).

 a)    11

b)    17

c)    22

d)    27

e)    44