Cullen works many odd jobs in order to save money for college. He makes extra money by mowing his grandfather's lawn, detailing cars, and walking his neighbor's dog. Cullen has a solid work ethic and truly values the money he makes. Cullen's family is very proud of his dedication to providing for himself. What is the central idea of this paragraph?

A. Cullen thinks detailing cars is the best way to make extra money.
B. Cullen is lazy and unmotivated.
C. Cullen spends much of his money on video games.
D. Cullen works hard at multiple jobs to save money for college.