How can a tax deduction for mortgage interest result in a subsidy for borrowers?

a. A tax deduction reduces taxable income, resulting in lower tax payments. This is only relevant for "itemizing" tax filers. The subsidy amount increases for people with higher income and larger mortgages.

b. A tax deduction reduces tax liability directly, resulting in lower tax payments. This is only relevant for itemizing tax filers. The subsidy amount increases for people with higher income and larger mortgages.

c. A tax deduction reduces taxable income resulting in lower tax payments. This policy is available to all tax filers. The subsidy amount increases for people with higher income and larger mortgages.

d. A tax deduction reduces tax liability directly, resulting in lower tax payments. This is available to all tax filers. The subsidy amount is a flat percentage of mortgage payments regardless of income or mortgage size.

e. None of the above.