Which of the following entities is NOT a type of real estate lien?

The entity that does not qualify as a type of real estate lien is the adjustable lien. In real estate, liens are legal claims or holds on properties, typically as a result of debts or obligations concerning the property.

A general lien can attach to all of a person's assets, not just a specific property. It often arises from situations like court judgments or tax debts that involve multiple properties owned by the same individual.

An equitable lien is another established type that arises from a court order or from a written contract, often to ensure that a party’s rights are honored in matters regarding the property.

A specific lien is focused on a particular asset or property, such as a mortgage lien that secures a loan against one specific piece of real estate, or a mechanic's lien for unpaid work on a property.

In contrast, "adjustable lien" is not a recognized category within lien types in real estate, making it the answer that does not fit within the established classifications.