Sam is a self-employed Engineer who maintains a qualifying office in his home. Sam has $110,000 gross income from his practice and incurs $95,000 in salaries, supplies, computer services, etc. Sam's mortgage interest and real estate taxes allocable to the office total $7,500. Other expenses allocable to the home office total $20,000 and consist of depreciation, utilities, insurance, and maintenance. What is Sam's total home office expense deduction? (Tax year 2018)

A) $10,000

B) $15,000

C) $20,000

D) $95,000