Which type of control should be used to implement custom controls that safeguard data?

The application level is the correct type of control to implement custom controls that safeguard data because it directly addresses security measures related to the software and applications that handle data. At the application layer, security can be fine-tuned to protect sensitive information through mechanisms such as data encryption, authentication, access controls, and input validation. These mechanisms are essential for creating custom solutions tailored to specific data protection requirements.

By focusing on application-level controls, organizations can effectively apply security measures that respond to the unique needs of their applications and the data they process. This flexibility is crucial, especially in environments where data privacy regulations and compliance requirements are stringent. Additionally, application-level controls allow for monitoring and logging activities, which enhance security by providing visibility into how data is accessed and processed.

In contrast, the other options do not specifically address the implementation of custom safeguards at the data handling level. Public and internal sharing and options for access are more about data sharing and user permissions, while the management plane primarily focuses on administrative operations and configurations within cloud services. Therefore, application-level controls stand out as the most effective choice for establishing tailored data protection strategies.