Which of the following statements is correct concerning the Days' sales in raw materials inventory?

a. A measure of how long it takes raw materials to be used in production.

b. The ratio is not useful for a manufacturer.

c. Reveals how many times a company turns over its raw materials inventory in a period.

d. Most companies generally prefer a higher number of days' sales in raw materials inventory.

e. Is calculated by taking the Raw materials used/Average raw materials inventory.