Explanation

Correct Answer: C

Why Option C is correct:

1. Cost minimization: Gateway VPC endpoints for S3 are free (no hourly charges or data processing fees). The only cost is the standard S3 data transfer and storage costs.
2. Prevents internet traversal: Gateway VPC endpoints allow traffic between the VPC and S3 to stay within the AWS network, avoiding the public internet.
3. Route table association: Associating the endpoint with all route tables ensures that all subnets in the VPC can use the endpoint.

Why other options are incorrect:

Option A (S3 Intelligent-Tiering):

• This is a storage class optimization feature that automatically moves data between access tiers based on access patterns.
• It helps reduce storage costs but does NOT prevent traffic from traversing the internet.
• The application still needs to access S3 over the internet unless combined with other networking solutions.

Option B (S3 Transfer Acceleration):

• This feature uses CloudFront's edge locations to accelerate uploads to S3.
• It actually routes traffic through the internet (via CloudFront edge locations), which contradicts the requirement to prevent internet traversal.
• It may increase costs due to CloudFront data transfer charges.

Option D (Interface endpoint for Amazon S3):

• Interface endpoints (AWS PrivateLink) are available for many AWS services, but for S3 specifically, gateway endpoints are the recommended and cost-effective solution.
• Interface endpoints incur hourly charges and data processing fees, which would increase costs.
• Gateway endpoints are specifically designed for S3 and are more cost-effective.

Key AWS Concepts:

• Gateway VPC Endpoint: A horizontally scaled, redundant gateway that allows private connectivity between VPC and supported AWS services (like S3) without requiring an internet gateway, NAT device, VPN connection, or AWS Direct Connect.
• Interface VPC Endpoint: Uses AWS PrivateLink technology and provides private connectivity to services that support it, but typically incurs costs.
• For S3 access from within a VPC, gateway endpoints are the most cost-effective solution for keeping traffic within AWS network.

Additional Considerations:

• The application processes 1 TB of data daily, so keeping this traffic within AWS network avoids potential internet bandwidth costs and improves security.
• Gateway endpoints work with S3 bucket policies and IAM policies to control access.
• This solution meets both requirements: minimizing costs (free endpoint) and preventing internet traversal (traffic stays within AWS network).