Katana owns a duplex. Both units were rented all year at rental value. Katana took care of the lawn maintenance during the summer months, but she did not provide any other services. In 2021, Katana paid $650 for homeowners insurance, $3,480 for mortgage interest, $250 in repairs, and $1,250 in real estate taxes for the whole building. Where are these deductions reported on her tax return?

a. As itemized deductions on Schedule A.

b. As an adjustment to income on Schedule 1 (Form 1040), Part II.

c. As expenses on Schedule C, Part II.

d. As expenses on Schedule E, Part I.