Final answer:
The purpose of consideration in a contract is to provide evidence that something of value is being exchanged between the parties involved.
Step-by-step explanation:
The purpose of consideration in a contract is to provide evidence that something of value is being exchanged between the parties involved. Consideration is a key element of a valid contract, and it is what distinguishes a contract from a mere promise.
For example, if you agree to sell your car to someone for $10,000, the consideration is not only the money but also the car that is being exchanged.
Therefore, option b. To provide evidence that something of value is being exchanged best describes the purpose of consideration.