Final answer:
Built-in monitoring is provided by the database system, while Additional Monitoring requires third-party tools.
Step-by-step explanation:
When monitoring an unmanaged database (NoSQL), there are two types of monitoring: Built-in monitoring and Additional Monitoring.
The difference between Built-in monitoring and Additional Monitoring is that Built-in monitoring is provided by the database system itself, while Additional Monitoring requires the use of third-party tools. Built-in monitoring is already included within the database system, while Additional Monitoring needs to be set up separately.
Therefore, option (a) is the correct answer: Built-in monitoring is provided by the database system, while Additional Monitoring requires third-party tools.