Final answer:
A good API should include documentation for usage, robust security to protect data, and backward compatibility to prevent disruptions with updates.
Step-by-step explanation:
A good API should include a variety of elements that ensure functionality, security, and ease of use. Three key elements are documentation, security, and backward compatibility. First, documentation is essential for developers to understand how to use the API effectively. It should include details on how to make requests, what parameters are required, and the expected response. Secondly, security is critical to protect the data and ensure that only authorized users have access. This might involve authentication, encryption, and secure protocols. Lastly, backward compatibility ensures that when updates are made to the API, it does not break existing integrations, allowing developers' applications to continue functioning without immediate need for changes. Therefore, the correct answer is b) Documentation, Security, Backward compatibility.