Final answer:
Daniela, who filed jointly with Lucas, might benefit from filing Form 8379, since Lucas owes back child support which could affect their joint refund. Form 8379 enables the non-debtor spouse to protect their share of the tax refund from being used to cover the debtor spouse's obligations.
Step-by-step explanation:
The taxpayer who might benefit from filing Form 8379, Injured Spouse Allocation, is b) Daniela, whose refund from a joint return with Lucas, a stay-at-home dad who owes back child support, could potentially be affected. This form allows Daniela to possibly retain her portion of the tax refund that rightfully belongs to her, separate from her spouse's debt.
Form 8379 is utilized when one spouse does not want their portion of a joint tax refund applied to the other spouse's past-due federal debts, state income tax obligations, child or spousal support payments, or federal non-tax debt (like a student loan). In the given scenarios, Daniela is affected because refunds can be seized to cover Lucas' obligation. The other scenarios describe situations where the spouse's owed debts (Bobby's tax misrepresentation, Forrest's delinquent student loans, Ryan's unpaid car payments for his ex-wife) do not specifically mention federal obligations that would typically cause a tax refund to be intercepted, nor do they suggest that the innocent spouse contributed income to the tax return.