Which of the following is the least profitable investment for a candy shop that earns $1 profit per pound of candy?

AWorker at $10 per hour, producing eight pounds of candy per hour

BWorker at $12 per hour, producing 16 pounds of candy per hour

CMachine with $5 per hour operating cost, producing 10 pounds of candy per hour

DMachine with $8 per hour operating cost, producing 14 pounds of candy per hour