A review of the 2019 tax file of Gregory, a single taxpayer who is age 40, provides the following information regarding Gregory's 2019 tax status: Adjusted gross income $40,000 5,000 Medical expenses (before percentage limit) Itemized deductions other than medical 12,000 12,200 2019 potential standard deduction In 2020, Gregory receives a reimbursement for last year's medical expenses of $1,200. As a result, Gregory must O A. reduce 2020's medical expenses by $1,200. B. include $800 in gross income for 2020. O C. amend the 2019 return. O D. include $1,200 in gross income for 2020.