The taxpayer covered by an employer retirement plan in 2018 who may qualify for a full deduction of their traditional IRA contribution is

1) Kelli, who files single with modified AGI of $64,000

2) Mark, who files head of household with modified AGI of $65,000

3) Samantha, who is filing a joint return as a surviving spouse with modified AGI of $96,000

4) Donald, who is married, filing a joint return with modified AGI of $101,500