Nashville Company manufactures nylon arm-band carriers for use with popular portable audio devices. Variable costs are $30 per arm-band carrier, the price is $100, and fixed costs are $280,000 per month. If Nashville Company earns a profit of $210,000, how much is the safety margin in terms of sales?

A. $700,000

B. $100,000

C. $300,000

D. $200,000

E. None of these.