Answer:
C for each additional hour of service, the price of the dog walker increases by $10
Explanation:
substitute any hour in f(n)=5+10n
for example, 1hr is 5+10×1=$15
2hr is 5+10×2=$25
3hr is 5+10×3=$35
4hr is 5+10×4=$45
and so on....
you can see that the price increases every $10