At current activity volume of 100 units, total fixed costs are $1,000 and total variable costs are $2,000. Next month, activity volume will decrease to 80 units. Predict unit cost (total cost per unit) for next month. $20 per unit $12.5 per unit $30 per unit O $10 per unit $32.5 per unit Breakeven volume is 400 units. Current sales volume is 500 units. The selling price is $50 per unit. The margin of safety is: 100 units 0 75% 25% O 20% 80%