Final answer:
The IRS has the power to lien both personal and real property, which is considered a general but involuntary encumbrance.
Step-by-step explanation:
The correct answer is d. General but involuntary. When the IRS places a lien on someone's property, it is considered a general encumbrance because it affects all property owned by the taxpayer. It is also considered involuntary because the lien is imposed by the IRS without the taxpayer's consent.