Evidence of prior negotiations, prior agreements, or contemporaneous oral agreements that contradict or vary the terms of a written contract may not be introduced into a trial. this is known as:

Parol evidence rule.

Explanation:

Parol evidence rule is the regulation that restricts the presentation of any evidence while oral contract before the existing period negotiation that can tend to manipulate, alter or contradict the terms mentioned in the written contract .

This law usually comes into action when some particular terms and expression of contract is being determined or completed. This rule is implied because it can change the contract or agreement when it has already reached the final stage. This law is followed in Anglo-American region.

answer; inductive techniques;