To upload photos to an S3 bucket using Amazon CloudFront with a custom domain name, the following components are required:
ACM in us-east-1 (Option A): When using CloudFront with HTTPS, the SSL/TLS certificate must be created in theus-east-1Region. AWS Certificate Manager (ACM) handles the provisioning, management, and renewal of public certificates, making this a cost-effective and low-maintenance solution.
S3 Transfer Acceleration (Option C): Transfer Acceleration allows faster uploads to S3 from CloudFront by routing traffic through AWS's edge locations. This significantly speeds up the data upload process, especially for users that are geographically distant from the S3 bucket's region.
Option B (ACM in eu-west-1): CloudFront only supports certificates created in us-east-1.
Option D and E (OAC and website endpoint): These are not ideal for handling secure uploads or efficient data transfers in this case.
AWS References:
Using ACM with CloudFront
Amazon S3 Transfer Acceleration

* EC2 Account Attributes: Amazon EC2 allows you to set account attributes to automatically encrypt new EBS volumes. This ensures that all new volumes created in your account are encrypted by default.
* Configuration Steps:
* Go to the EC2 Dashboard.
* Select "Account Attributes" and then "EBS encryption".
* Enable default EBS encryption and select the default AWS KMS key or a customer-managed key.
* Prevention of Unencrypted Volumes: By setting this account attribute, you ensure that it is not possible to create unencrypted EBS volumes, thereby enforcing compliance with security requirements.
* Operational Efficiency: This solution requires minimal configuration changes and provides automatic enforcement of encryption policies, reducing operational overhead.
References:
* Amazon EC2 Default EBS Encryption

Kinesis Data Streams is the right ingestion service for real-time streaming data, and AWS Lambda is the least- operations compute option for processing and transforming records from the stream. AWS documents that Lambda can process events from stream sources such as Kinesis without infrastructure management. Storing the transformed data in DynamoDB provides durable, scalable storage for later analysis. The EC2 option introduces server management overhead. SQS is useful for queued work, but the question specifically centers on streaming data. SNS with ElastiCache is also not a durable analysis store design. Therefore, Kinesis Data Streams plus Lambda plus DynamoDB is the lowest-overhead architecture among the choices.

Amazon EFS provides a fully managed, highly available, and shared file system that can be mounted by instances across multiple Availability Zones. This ensures consistency of files between EC2 instances and avoids replication issues. EBS volumes, in contrast, are AZ-scoped and not designed for multi-instance sharing. Options A and B rely on custom replication or manual file handling, which increases operational overhead and risks inconsistencies. Option D does not solve the shared access and consistency requirement.
By migrating storage to EFS, both EC2 instances will read and write to the same storage system, ensuring that users always access the latest files without 404 errors.
References:* Amazon EFS User Guide - Accessing data across multiple Availability Zones* AWS Well- Architected Framework - Reliability Pillar: Data durability and consistency

Option B (Amazon FSx for Lustre): FSx for Lustre is optimized for high-performance file systems required by HPC workloads, scaling to millions of IOPS and supporting parallelized data access.
Option E (Cluster Placement Group with Auto Scaling): A cluster placement group ensures low-latency communication between EC2 instances, critical for HPC workloads. Amazon EMR simplifies running large- scale analytics jobs.
Amazon FSx for Lustre Documentation,AWS Placement Groups Documentation