What constitutes a 'contract'?

A contract is defined as a legally enforceable agreement among parties, which means that it creates rights and obligations that are recognized by law. For an agreement to be considered a contract, it typically must include key elements such as an offer, acceptance, consideration (something of value exchanged), and the intention to create legal relations. When these elements are present, the parties involved are legally bound to adhere to the terms of the contract.

The other options do not meet the criteria for a contract. A legal obligation to perform community service can arise from various legal contexts but does not inherently reflect a contractual agreement between parties. An informal agreement between friends lacks the formalities and often the intention to create legal obligations. A non-binding verbal promise may represent an intention to act or a willingness to do something but is not typically enforceable by law unless it meets the criteria for a contract, making it insufficient on its own. Thus, option C accurately captures the essence of what constitutes a contract.