Which of the following statements regarding the married, filing jointly status is false?

a. Marital status is determined as of the last day of the year when a spouse dies during the year.

b. Filing a joint return carries the potential disadvantage of joint and several liability.

c. If married persons filing separately, they can change later to a joint return.

d. Once a joint return has been filed and the due date has passed for a particular year, the spouses cannot switch to separate returns for the year.

e. Marital status is determined as of the last day of the tax year.