Final answer:
The standard deduction for a taxpayer filing as Married Filing Jointly or Surviving Spouse in the 2017 tax year is $12,700, which is used to determine their taxable income and calculate their tax liability.
Step-by-step explanation:
The taxpayer's standard deduction for the 2017 tax year, assuming the filing status is Married Filing Jointly or Surviving Spouse, is $12,700. This information is crucial for calculating one's total tax liability. When completing their tax return, the taxpayer should subtract this standard deduction amount from their gross income to determine their taxable income, which is then used to calculate their tax liability based on the relevant tax rates and potential credits, such as the earned income tax credit (EITC).