Final answer:
In a QTIP marital deduction trust, the surviving spouse must have a limited power of appointment.
Step-by-step explanation:
In a QTIP marital deduction trust, the surviving spouse must have a limited power of appointment (option a).
A QTIP trust, which stands for Qualified Terminable Interest Property trust, is a type of trust that allows a person to provide for their surviving spouse while also controlling how the assets are distributed after the surviving spouse's death.
A limited power of appointment gives the surviving spouse the authority to direct the assets of the trust to certain beneficiaries, but with limitations. The spouse can only appoint the assets among a specified group of beneficiaries, and they cannot appoint the assets to themselves or their estate.