In general, when a contract has been reduced to writing with the intent that the writing represents the complete and final expression of the parties' intentions, no party can introduce oral or written words outside the "four corners" of the agreement to add to$,$ change, or contradict the writing if that evidence existed at the time of$,$ or prior to$,$ the writing. This is known as which of the following?

Multiple choice question.

The Statute of Frauds

The commercial impracticability doctrine

The substantial performance doctrine

The parol evidence rule