Which of the following is necessary for the legal object of a contract?

For a contract to be considered legally binding, it is essential that the object of the contract is legal and executable within the confines of the law. This means that the purpose or subject matter of the contract must not involve any illegal activities or obligations. If the object of a contract is illegal, it will render the entire contract void and unenforceable.

Contracts that involve illegal activities, for instance, are unenforceable in a court of law. Therefore, ensuring that the object is lawful is a fundamental requirement for a contract to be valid. This principle applies universally across various types of contracts, not just those related to real estate transactions.

In contrast, the other options do not represent necessary legal criteria. While defined deadlines may enhance a contract and clarify expectations, they are not universally needed for legality. Similarly, while multiple parties typically exist in a contract, a contract can still be valid with a single party under certain conditions (like unilateral contracts). Finally, while real estate transactions have specific regulations, a legal object isn’t restricted to them alone, encompassing a broad spectrum of lawful agreements. Ensuring the legality of the object is the cornerstone of contractual obligations.