E. Johnston Company wants to double production of Product X from 1,000 units to 2,000 units. The variable manufacturing cost per unit is $15. The variable non- manufacturing cost per unit is $30. There are no fixed costs. The selling price per unit is $50. What is the incremental cost of the proposed change? A. $15,000 B. $30,000 C. $60,000 D. $45,000 Which of the following costs is a variable cost? A. rental expense for factory building for manufacturer of electronics. B. lease cost for factory machine for manufacturer of electronics. C. fuel for airplane for airline. D. Depreciation expense of airplane for airline