Delaware Code Title 30. State Taxes § 1161. Persons required to make returns of income

a. Is required to file a federal income tax return for the taxable year, or

b. Is a single person and has for the taxable year adjusted gross income as modified by § 1106 of this title of more than $9,378, or

c. Is a married individual who is entitled to file a joint federal income tax return for the taxable year, and whose adjusted gross income for the taxable year as modified by § 1106 of this title, when combined with the adjusted gross income of the individual's spouse, is more than $15,449.