Which of the following is NOT a key element of a binding contract?

A binding contract typically includes several key elements, and while witness signatures can provide validation and support in certain contexts, they are not essential for the creation of a legally binding contract.

Competent parties are necessary to ensure that those entering into the contract have the legal capacity to do so, meaning they are of legal age and mentally capable. Mutual assent refers to both parties agreeing to the terms of the contract, often indicated through an offer and acceptance. Consideration involves something of value being exchanged between the parties, which is necessary to differentiate a contract from a mere promise. Conversely, witness signatures, while useful in some cases for evidentiary purposes, are not a fundamental requirement in most scenarios where contracts are enforced.

This distinction highlights that witness signatures are not always needed for a contract to be valid, making it the correct answer to the question regarding what is NOT a key element of a binding contract.