How does a just-in-time inventory system benefit a firm? what conditions are needed for its succesful use?

Multiple choices are:

the firms relation with the supplier is the most critical factor to the success of a just-in-time inventory system

		a just-in-time inventory system benefits a firm because it will reduce total cost
		a just-in-time inventory system benefits a firm because it will reduce inventory holding cost
		costs due to factors other than inventory holding cost can make a just-in-time inventory system more costly than a regular inventory system
		A and B
		A and C
		A and D
		B and C
		B and D
		C and D
		all but A
		all but B
		all but C
		all but D
		all are true