W, who is unmarried and files a single return, had adjusted gross income of $50,000 in 2020. The following is a list of W's itemized deductions for 2020, before any percentage limitations:

Unreimbursed medical expenses$6,000

Charitable contributions2,000

Interest paid on home mortgage5,000

State and local income taxes3,250

In 2021 W received $6,000 as reimbursement from his health insurance company. How much of the reimbursement must W include in his 2021 gross income?

a.$100

b.$3,850

c.$6,000

d.$2,250

e. $5,000

f.None of the above.