Final answer:
Ned can only include $600 as a deductible medical expense for the health insurance premiums. Auto insurance, room and board, and travel costs are not deductible as itemized deductions.
Step-by-step explanation:
In the context of the Internal Revenue Service's (IRS) rules for deductible expenses, it's important to understand that not all personal expenditures can be included in itemized deductions. The expenditures made by Ned for Todd's support don't all qualify as deductible expenses. Specifically, expenditures such as auto insurance premiums, room and board at school, and travel costs are not deductible as itemized expenses or miscellaneous itemized deductions.
However, health insurance premiums paid by Ned that are not through an exchange may qualify as deductible medical expenses, assuming they meet the criteria set by IRS such as not being reimbursed by an employer. Therefore, Ned can include $600 as medical expenses in his itemized deductions, assuming they exceed 7.5% of his adjusted gross income (AGI). This would make answer choice D the correct option.