Final answer:
Nominal consideration is often used to make gratuitous promises seem like true bargains, though it is not listed among the provided options. In the context of the given choices, illusory promises are the closest in practice, used to give the impression of a bargain where one may not truly exist.
Step-by-step explanation:
The element often used by agreements to make gratuitous promises appear as true bargains is nominal consideration. Nominal consideration refers to a token amount specified in a contract, often a dollar, used to fulfill the legal requirement for a contract to have consideration. However, nominal consideration is not actually one of the options provided in the question.
Among the provided options, illusory promises are sometimes used in an attempt to create the semblance of a bargain when there's actually no firm commitment. An illusory promise is a statement that appears to configure a contractual obligation but, upon closer inspection, lacks the substance and commitment required for a contract to be enforceable as it allows one party to escape performance.
An illusory promise is a promise that is unenforceable due to indefiniteness or lack of mutuality, where only one side is bound to perform.