Which couple may NOT use the married filing jointly status on their federal income tax return?

Married couples typically have the option to file jointly, but certain conditions can restrict this status. The correct answer involves Mark and Beth, who have different fiscal years. The IRS requires that for a married couple to file jointly, they must both have the same tax year. If one spouse is on a calendar year and the other is on a fiscal year, they cannot file a joint return.

In contrast, couples like Terry and Edie, who have moved to separate homes, can still file jointly as marital status is determined by the last day of the tax year rather than living arrangements. Similarly, Paul and Josie, despite their recent marriage on New Year's Eve, are eligible to file jointly for that tax year since they were married by December 31. Lastly, Sara and Jack can also file jointly even if Jack has no income, as the ability to file jointly does not depend on both spouses having earned income. Thus, the only scenario that disqualifies the couple from filing jointly is due to having different fiscal years.