Answer: A)
Explanation:
In this case, Mark, Drue and Ed are labor. There are 3 more main factors in productions which are capital, land and enterprise.
Labor is considering workers and their work for the man that they are working, in this case, Mr. Smith. Capital is considering machines and other elements that the workers are using and we here have truck, edger, weed eater and lawnmower as Capital. Mr. Smith is considering the enterprise and his worker are using land and capital for the business that the are doing for him.