How can these requirements be satisfied?

Explanations:

Creating a VPC endpoint allows private connections between the VPC and Amazon S3 without traversing the public internet. By applying a bucket policy that restricts access to the specific VPC endpoint, you ensure that only resources within that VPC can access the data, satisfying the requirement for data accessibility from a VPC only and preventing public internet access.

While a VPC endpoint can be created, applying a bucket access policy that allows access from both the VPC endpoint and an Amazon EC2 instance introduces a potential risk. If the EC2 instance is accessible from the public internet, it could allow unauthorized access to the dataset, violating the requirement to keep the data secure and not traversing the public internet.

Using Network Access Control Lists (NACLs) to control access between the VPC endpoint and an Amazon EC2 instance does not sufficiently restrict access. NACLs are stateless and could allow traffic from other sources, which does not guarantee that access to the S3 bucket is limited solely to the VPC, thus failing to meet the requirement for security against public internet exposure.

While security groups can restrict access, they are stateful and only control traffic to the instances, not to the S3 bucket directly. A VPC endpoint with a proper bucket policy is essential to ensure that only the VPC can access the S3 data. Relying solely on security groups without a proper bucket policy means there could still be potential access from other sources, which does not comply with the security requirements.