Which methods to approximate cost function involves a detailed analysis of what cost behavior should be, based on evaluation of the production methods to be used the materials specifications, labor requirements, equipment usage, production efficiency, power consumption, and so on? Select one: O a activity analysis; account analysis O b. high low method O c. least-squares regression analysis O d. None of the answers given O e. engineering approach The break-even point is that level of activity where: Select one: O a sales revenue equals total variable cost. Ob profit equals to zero. O c total contribution margin equals the sum of variable cost plus fixed cost. Od total revenue equals total fixed cost. e. variable cost equals fixed cost