The manufacturing costs of Heather Industries for three months of the year are provided below. Total Costs Production January February March $187,920 196,900 292,320 2,520 units 3,890 units 6,120 units Using the high-low method, determine (a) the variable cost per unit and (b) the total fixed cost. Round all answers to the nearest whole dollar. a. Variable cost per unit b. Total fixed cost