Given QM output on a product-mix problem as below:

Objective: Maximize

Results ----------

X1 X2 RHS Dual

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Maximize 40 50

Material A 1 2 <= 40 16

Material B 4 3 <= 120 6

Material C 2 7 <= 300 0

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Solution 24 8 1,360

The dual value for Material C is 0, which means ______________.

		Material C is not used at all in producing X1 and X2
		Additional Material C would not make objective function value change
		Material C is a useless resource for the production
		Material C can be obtained for free