Does Mary need to file a tax return based on her gross income?

Mary needs to file a tax return because her income exceeds the threshold established by the IRS for the tax year in question. Each year, the IRS defines specific income thresholds that determine whether an individual is required to file a tax return. These thresholds vary based on factors such as filing status (single, married, head of household, etc.) and age.

When a person's gross income exceeds the applicable threshold, they are generally required to file a tax return. This requirement exists to ensure compliance with tax laws and allows individuals to report their income accurately, claim deductions or credits they may qualify for, and fulfill their tax obligations.

The other choices reflect different scenarios: simply being below the threshold or being over the age of 65 may influence whether someone needs to file; however, if the income surpasses the IRS threshold, the requirement to file takes precedence. Similarly, the mention of Sandi’s filing does not impact Mary’s own filing requirements, as each individual's tax obligations are determined independently based on their respective income levels.