Lincoln, Inc., which uses a volume-based cost system, produces cat condos that sell for $100 each. Direct materials cost $18 per unit, and direct labor costs $19 per unit. Manufacturing overhead is applied at a rate of 100% of direct labor cost. Nonmanufacturing costs are $31 per unit. What is the gross profit margin for the cat condos? (Round your intermediate calculations to nearest whole dollar.)

a) 44.0%

b) 13.0%

c) 69.5%

d) 87.0%