Paul is a self-employed taxpayer. He has the following transactions: Business gross income $85,000 Property tax on the office $6,000 Rental expenses on business equipment $3,000 Payment of his health insurance $6,000 Business entertainment costs $500 Unreimbursed medical expenses for himself and his dependents $4,500 Other business expenses $15,000 What is his net business income? A. $70,000 B. $61,000 C. $55,000 D. $50,500