Final answer:
The $10,000 distributed from a traditional IRA should be reported as taxable income on line 4b of Form 1040 because the taxpayer had not made any non-deductible contributions.
Step-by-step explanation:
The question pertains to determining the amount of income to be reported from a traditional IRA distribution when filling out Form 1040 for income tax purposes. If the taxpayer has only made deductible contributions to their traditional IRA and they receive a distribution, the total distribution amount is generally considered taxable income. As per the details provided, since the taxpayer didn't make any non-deductible contributions, there's no need for Form 8606, which is used for reporting such contributions. Therefore, the entire distribution amount of $10,000 would typically be reported as taxable income on line 4b of Form 1040.