Which of the following can be a characteristic of a contract?

A characteristic of a contract is that it can be oral, meaning that verbal agreements can constitute a valid contract under certain circumstances. In many legal systems, including Louisiana law, contracts do not always have to be in writing to be enforceable. As long as the parties involved mutually agree to the terms and intend to create a binding agreement, an oral contract can be valid.

Given that some contracts must be in writing to be enforceable, particularly those involving certain transactions like the sale of real estate, it is not accurate to assert that all contracts must be in writing. Furthermore, contracts can have both explicit terms (clearly stated) and implicit terms (understood but not stated) and can involve more than two parties, as multi-party contracts are common in business and legal practices. Thus, the flexibility of oral agreements as characteristics of contracts makes this the appropriate answer.