Inventory control models assume that demand for an item is:
a. always dependent on the demand for other items.
b. either independent of or dependent on the demand for other items.
c. always independent on the demand for other items.
d. identical to the demand for other items.

b.

Explanation:

Inventory control models assume that demand for an item is either independent of or dependent on the demand for other items. This is because the amount of stock that the company should have for an item depends on the demand for that item, but at the same time demand for that item will sometimes vary depending on the demand for other similar items which may or may not be taking market share away from the first item.

answer; coefficient of correlation;