In ‘make or buy’ decision, it is profitable to buy from outside only when the supplier’s price is below the firm’s own ______________.

Answer: Option B

In ‘make or buy’ decision, it is profitable to buy from outside only when the supplier’s price is below the firm’s own Variable Cost. A variable cost is a corporate expense that changes in proportion to production output. Variable costs increase or decrease depending on a company's production volume; they rise as production increases and fall as production decreases.