Which of the following is a principle that allows an easement to become irrevocable?

The principle that allows an easement to become irrevocable is equitable estoppel. This legal doctrine prevents a party from asserting something contrary to what is implied by a previous action or statement of that party if it would result in harm to another party who reasonably relied on that action or statement. In the context of easements, if a property owner permits another party to use their land and that party invests significant resources into that use based on the owner's implied or explicit permission, the owner may be estopped from revoking that easement. Essentially, equitable estoppel serves to protect the reliance of the party using the easement, ensuring that they can continue to do so without the risk of sudden termination due to the property's owner's change of mind.

The other principles mentioned, such as the Statute of Frauds, govern the formal requirements for contracts, including the need for certain agreements to be in writing, but they do not address the irrevocability of easements. Deed restrictions relate to limitations placed on a property by its title or deed, not directly affecting the status of easements. Adverse possession pertains to acquiring title to property through continuous and hostile use over time, which doesn't transform an easement into an irrevocable right but rather relates to possessing