Choice "C" is correct. Just-in-time purchasing systems usually results in a reduction in the number of suppliers. Because a company that adopts J-I-T is very dependent on supplier performance, usually fewer suppliers are used and a very close working relationship is developed with existing suppliers.
Choice "d" is incorrect. Just-in-time requires more deliveries from suppliers.
Choice "b" is incorrect. Usually there is more reliance on quality control by the supplier. Finding defective goods as they arrive is too late; a stock-out could cause production to shut down.
Choice "a" is incorrect. There is much more need for linkage with the vendor's order entry system with J-I-T because the company is dependent on timely deliveries from the vendor.