Explanation

Correct Answer: C

Amazon SNS supports dead-letter queues (DLQs) to capture messages that cannot be delivered to subscribers. When configuring an SNS subscription to an HTTPS endpoint, you can set up a DLQ to capture undeliverable messages. The most appropriate solution with the least development effort is:

1. Amazon SNS Dead Letter Queue with Amazon SQS target - This is a native integration where SNS can directly send failed messages to an SQS queue.
2. SQS Retention Period - SQS queues can be configured with a message retention period of up to 14 days (maximum is actually 14 days).

Why Option C is correct:

• Least Development Effort: SNS has built-in support for SQS as a DLQ target. This requires minimal configuration.
• Retention Period: SQS supports message retention up to 14 days, meeting the requirement.
• Analysis Capability: Messages in SQS can be easily analyzed using standard AWS tools or by consuming the queue.

Why other options are incorrect:

Option A (Kinesis Data Stream):

• Kinesis Data Streams have a maximum retention period of 365 days, but this requires more development effort to set up and analyze.
• Not a native DLQ target for SNS like SQS is.
• More complex to implement and analyze messages.

Option B (Add SQS queue between application and SNS):

• This changes the architecture fundamentally by inserting a queue before SNS.
• Doesn't address the specific requirement of capturing undelivered messages from SNS to HTTPS endpoint.
• Would require application changes to send to SQS instead of SNS.

Option D (DynamoDB with TTL):

• While DynamoDB can store messages, it's not a native DLQ target for SNS.
• Requires more development effort to set up Lambda functions or custom code to write failed messages to DynamoDB.
• TTL in DynamoDB deletes items automatically, which might not be ideal for analysis.

Key AWS Concepts:

• SNS Dead Letter Queues: Capture messages that cannot be delivered to subscribers after maximum retries.
• SQS Retention: Configurable from 1 minute to 14 days (default is 4 days).
• HTTPS Endpoint Subscription: When SNS sends to HTTPS endpoints, delivery failures can occur due to endpoint unavailability, timeouts, or HTTP errors.

Best Practice: Use SQS as DLQ for SNS when you need to retain and analyze undelivered messages with minimal development overhead.