Ms. Oak was divorced on January 1 of the current year. She had an unmarried son living in her home for the entire year. It cost $3,000 to maintain Ms. Oaks home for the year, of which she contributed $2,000 and Joe Oak, her ex-husband, contributed $1,000 through support payments. Joe Oak, however, provides more than half of the sons total support and claims him as his dependent, as Ms. Oak signed a waiver. Which is the most advantageous filing status for which Mrs. Oak can qualify?

a. Married filing joint return.

b. Head of household.

c. Married filing separately.

d. Single.