Answer: Contracts
Step-by-step explanation:
The contract is the mechanism which is basically used by the developers to follow the set of rules that is defined in the framework with the proper specification in the API ( Application programming interface).
The contract is the proper agreement between the two and more developers so that they must follow the rules that is mentioned in the agreement contract.
The contract is widely used in the software development process in which all the possible design requirement are mentioned according to the needs of the client.
Therefore, Contract is the correct option.