XYZ Inc. sells a single product for $10 per unit. Variable production costs are $5 per unit. Fixed overhead costs amount $10,000 per month. Variable selling costs are $2 per unit. Fixed selling costs are $10,000 per month. Last month, the company produced 10,000 units and sold 8,000 units. What were XYZ's total selling costs incurred last period?

• $80,000

• $26,000

• $15,000

• $13,000