For the coming year, River Company estimates fixed costs at $109,000, the unit variable cost at $21, and the unit selling price at $85. Determine the following: If required, round to the nearest whole unit and round interim calculations to one decimal place. Required: a. The break-even point in units of sales. units b. The unit sales required to realize operating income of $150,000. units c. The probable operating income if sales total $500,000