Answer:
C. the advantage is that regardless of the size of the estate it can be transferred tax-free and the disadvantage is that the IRS will find another way to tax the surviving spouse.
Step-by-step explanation:
Indeed, the unlimited marital deduction provision allows a spouse (either the husband or the wife) to transfer an unrestricted amount of assets (estate assets) to the other spouse at any time regardless of the size of the estate without any tax deduction.
However, even though the IRS is unable to deduct this, it will find another way to tax the surviving spouse because that's their job.