Within the relevant range, variable costs can be expected to: A) vary in total in direct proportion to changes in the activity level. B) remain constant in total as the activity level changes. C) increase on a per unit basis as the activity level increases. D) increase on a per unit basis as the activity level decreases. Which costs will change with a decrease in activity within the relevant range? A) Total fixed costs and total variable cost. B) Unit fixed costs and total variable cost. C) Unit variable cost and unit fixed cost. D) Unit fixed cost and total fixed cost. Fixed costs expressed on a per unit basis: A) increase with increases in activity. B) decrease with increases in activity. C) are not affected by activity. D) should be ignored in making decisions since they cannot change. In the standard cost formula Y = a + bx, what does the "Y" represent? A) total cost B) total fixed cost C) total variable cost D) variable cost per unit Which of the following costs could contain both variable and fixed cost elements with respect to the total output of the company? A) Sales commissions. B) Manufacturing overhead. C) Direct materials. D) Administrative salaries. A cost incurred in the past that is not relevant to any current decision is classified as a(n): A) period cost. B) opportunity cost. C) sunk cost. D) differential cost