The following taxpayers are covered by an employer-sponsored retirement plan. Which one may FULLY DEDUCT their traditional IRA contribution?

Kelli files single. Her modified AGI is $68,000.

Mark files head of household. His modified AGI is $68,001.

Samantha is married, did not live with her spouse at any time during the year, and chooses to file a separate return. Her modified AGI is $10,975.

Donald is married and files a joint return. Both he and his spouse are covered by an employer-sponsored plan. The couple's modified AGI is $109,500.