Opportunity Cost is the: a. Same as a sunk cost b. contribution to operating income forgone by not using a limited resource in its next-best alternative use c. Missed opportunity to increase contribution margin d. Most important cost on the Balance sheet Variable costing is: a. always the preferred costing method b. known to always have higher profit C. a method of inventory costing in which all variable manufacturing costs are included as inventoriable costs d. is GAAP compliant