I’m super confused pls help me!

Answer:
I don't understand the one-time fee parts but
Step-by-step explanation:
B. $140 = Hourly Rate
C. $50 =Hourly Rate
D. No, this is because no matter what A Plus Plumbing is going to charge more every hour than Quality Plumbing so every time the hour goes up A Plus Plumbing costs more than Quality Plumbing for example A Plus at 9 hours costs $1,000 while Quality would only cost $600.