Final answer:
Child support payments are not tax-deductible, but Child Tax Credit may apply. Real estate taxes and state income taxes (not provincial) can be deducted from federal income taxes. Student loan interest is also deductible, depending on eligibility.
Step-by-step explanation:
The options provided for reducing federal income taxes each have different qualifications for tax deductibility. Payments for child support are not deductible from your taxable income. However, you may be eligible for a reduction in your federal income taxes through the Child Tax Credit (CTC) if you have qualifying children, which can include a six-year-old dependent.
Real estate taxes paid on property you own can be deducted up to a certain limit, and are often included as part of itemized deductions on your tax return. Provincial income taxes do not apply in the United States, but state income taxes that you pay can be deducted from your federal income taxes.
Lastly, the interest paid on student loans may be deducted, subject to income limitations and other criteria. Each of these deductions aims to reduce your overall taxable income, thus potentially lowering the amount of taxes you owe to the federal government.