Which of the following statements is true?

a. In contract buying, price and delivery are negotiated each time an order is released.

b. Contract buying assures suppliers that they have a given amount of business and commits them to allocating that amount of their capacity to the customer.

c. Contract buying is useful for short-term purchases.

d. EDI does not eliminate much of the paperwork associated with buying.

e. None of the above is true.