8 Which one of the following statements is true? As a general rule, all individuals over age 18 must file a federal income tax return. As a general rule, all individuals who have any gross income for the year must file a federal income tax return. As a general rule, all individuals who are not dependents of someone else must file a federal income tax return. As a general rule, all individuals who have gross income in excess of their applicable standard deduction must file a federal income tax return