Final answer:
In contract law, giving a return promise, which is considered consideration, is what supports a contract. An illusory promise, past consideration, or a pre-existing public obligation do not provide the necessary support for a contract to be legally binding.
Step-by-step explanation:
The student's question asks which elements would support a contract. In contract law, a contract is a legally enforceable agreement between parties that creates mutual obligations. The options provided require examination to determine which can be considered as supporting a valid contract. Let's evaluate each one:
- An illusory promise is not binding because it lacks a firm commitment or obligation, thus it does not support a contract.
- Giving a return promise, or consideration, is essential to the formation of a contract. This mutual exchange of promises establishes that each party has agreed to give or do something in return for the other's act or promise.
- Past consideration refers to something given or some act done in the past, which cannot ordinarily be consideration for a later promise. Therefore, past consideration does not support a contract.
- A pre-existing public obligation is typically one that is already imposed by law, and fulfilling such an obligation cannot be considered a valid consideration for a new promise.
The correct answer is b) giving a return promise, as it satisfies the requirement of consideration which is a core element in the formation of a contract.