The hendersons have just bought a home that requires some monthly yard maintenance. they are trying to decide if they should hire a professional lawn care service to maintain the property or do it themselves. below are the costs associated with both options:

professional service option
do-it-yourself option
$75 for the first month
$250 lawnmower
$45 per month after initial visit
$135 edger
includes mowing and edging the lawn, trimming the bushes, and raking the leaves.
$69 hedge trimmer

$25 rake

how long would it take before the hendersons would recover their costs if they chose to do it themselves over the professional service?
a.
5 months
b.
9 months
c.
10 months
d.
6 months