You own a dog-walking business. You have 2 inputs, experienced dog walkers (Pros) and novice dog walkers (Newbies). Your output is dogs walked. Your Pros are able to walk more dogs per day than the Newbies can; the Pros each walk 28 dogs a day, so the MPPros is 28. Newbies each walk 16 dogs a day, so the MPNewbies is 16. The Pros are paid $100 per day and the Newbies are paid $60 per day. You are currently using 3 of each, 3 Pros and 3 Newbies. Which of the following is correct?

a) Total output of dogs walked is 144.
b) Total output of dogs walked is 144, and the total cost of labor is $540.
c) Total output of dogs walked is 144, and the total cost of labor is $660.
d) Total output of dogs walked is 144, and the total cost of labor is $720.