A company sells one of its products for $10.70 per unit. Its fixed costs are $680.00 per month, and the variable cost per unit is $3.90. (a) The contribution margin per unit is $ (rounded to the nearest cent). (b) The break-even volume, i.e., the level of output at break-even, is units per month. (If necessary, round up to the next whole number of units.) (c) The profit at a monthly output level of 172 units is $ (rounded to the nearest cent)