10. Which of the following statements concerning head of household status is not correct?

a. filing as head of household rather than single significantly reduces income taxes

b. taxpayer must pay more than half of the cost of keeping up the home

c. taxpayer must have custody of a child for over half of the year

d. may be married if he/she did not live with their spouse during the last 3 months of the year.

Please explain answer, thank you!