Final answer:
A promise not to smoke can constitute legal consideration in contract law because it is the sacrifice of a legal right, providing value in an agreement.
Step-by-step explanation:
A promise to refrain from smoking can be legal consideration because by agreeing to refrain from something one has the legal right to do, such as smoking, that person is providing a form of consideration. In contract law, consideration is defined as the value exchanged in a contract, and it can include actions, abstentions, or promises. Therefore, if a person is offering not to exercise their legal right to smoke as part of a bargain, it constitutes valid consideration as they are voluntarily giving up a right for the benefit of the other party involved in the contract.