A 42-year-old single taxpayer with AGI of $142,000 a year can make which of the following IRA contributions if he is not covered by a plan at work? a. $6,000 to either a traditional IRA, a Roth IRA, or a nondeductible IRA b. $6,000 to either a traditional IRA or a nondeductible IRA, but no contribution is allowed to a Roth IRA c. $6,000 to a Roth IRA only d. $7,000 to either a traditional IRA, a Roth IRA, or a nondeductible IRA