Which solution will help ensure that an Amazon EMR cluster is not exposed to the public internet when processing PII data?

The chosen solution focuses on enabling the block public access setting for Amazon EMR at the account level, which is effective in ensuring that EMR clusters are not exposed to the public internet. This setting helps prevent accidental exposure of Amazon EMR clusters to the public internet, which is crucial when processing sensitive data such as personally identifiable information (PII).

By applying this setting at the account level, it enforces rules that automatically block public access to Amazon EMR services, helping to maintain compliance and security standards. This is an essential layer of protection to reduce the risk of unauthorized access and data breaches.

In contrast, other options, while beneficial for security, do not directly address the overarching strategy of preventing public exposure. Creating an EMR security configuration is important for defining security measures, but it does not guarantee that public access is entirely blocked at a higher level. Regularly checking security group configurations may help maintain security compliance; however, it does not prevent public access on its own. Lastly, IP whitelisting can restrict access but requires continuous management and monitoring, which could be more error-prone and labor-intensive than implementing an account-level setting that automatically manages exposure.