An interface VPC endpoint does provide a direct connection between the EC2 instance and the S3 bucket. It enables private communication between instances in your VPC and resources in other services without requiring an internet gateway, a NAT device, or a VPN connection.
Option A , which recommends creating an interface VPC endpoint for Amazon S3 in the subnet where the EC2 instance is located and attaching a resource policy to the S3 bucket to only allow the EC2 instance's IAM role for access, is the correct solution for the given scenario. It meets the requirement to ensure that no API calls and no data are routed through public internet routes and that only the EC2 instance can have access to upload data to the S3 bucket.