The second answer i think is the best one
I honestly don't know because i'm only in sixth grade but I think that it might be 30*.
Depending on how big the center is, I would say 15.
I hope this helped!
The plumber worked for 5 hours because 450-200=250 which gets rid of the initial fee so 250 divided by 50 is 5
The idea for transitions for an equation like this is

where m = slope
h = how much left or right (note the negative)
k = how much up or down
moving 13 down would mean
k = -13
so

D. would be your answer