---In which of the following scenarios would the head of household filing status be available to the taxpayer?

A single taxpayer maintains a household that is the principal home for 5 months of the year for his disabled child.

A single taxpayer maintains a separate home for his parent, who qualifies as a dependent.

An unmarried taxpayer maintains a household with a 28-year-old son, who earned $10,000 during the tax year.

A taxpayer withnodependents is the surviving spouse of an individual who died in the current year.

---Which of the following represents the official interpretation of the Internal Revenue Code (IRC) and is (1) a primary authoritative source when conducting tax research and (2) binding on a court?

Private letter rulings.

Treasury regulations.

Revenue rulings.

Revenue procedures.

---Mr. and Mrs. X plan to file a joint return for 2019. Neither is over 65 or blind, nor do they have any dependents. What is the amount of gross income required before they must file a return?

$27,000

$12,200

$25,700

$24,400