An inventory decision rule states, "When the inventory level goes down to $14$ gearboxes, $100$ gearboxes will be ordered. "Which of the following statements is TRUE?

A$.$ Fourteen is the safety stock, and $100$ is the reorder point.

B$.$ One hundred is the reorder point, and $14$ is the order quantity

C$.$ The number $100$ is a function of demand during lead time.

D$.$ Fourteen is the reorder point, and $100$ is the order quantity.

E$.$ None of the above is true.