9. Frank is a self-employed architect who maintains a qualifying office in his home. Frank has $80,000 gross income from his practice and incurs $72,000 in salaries, supplies, computer services, etc. Frank's mortgage interest and real estate taxes allocable to the office total $3,000. Other expenses total $9,000 and consist of depreciation, utilities, insurance, and maintenance. Frank's total office in home deductions are a. $3,000