Roy services (Oil Change) vehicles in his garage. His lubricants cost him $40 per vehicle. His wages are $120 per hour. He spends 20 minutes per vehicle. His garage rent is $600 per month. He charges $140 to service each vehicle. His Contribution Ratio in servicing each vehicle is:

Select one:

a. 51%

b. 86%

c. 120%

d. 43%