Which task does AWS perform automatically? (CLF-C02)

Correct answer: A. Encrypt data that is stored in Amazon DynamoDB.
AWS automatically encrypts data that is stored in Amazon DynamoDB. DynamoDB is a fully managed NoSQL database service that automatically encrypts data at rest using AWS Key Management Service (KMS) keys. This means that data is encrypted as soon as it is written to the database, and decrypted when it is read.

The other options are not correct because:
B. Patching Amazon EC2 instances is a task that is typically performed by the customer. While AWS provides security patches and updates for the underlying operating system and software, it is the customer's responsibility to apply these patches to their EC2 instances.
C. Encrypting user network traffic is a task that can be performed using AWS services such as AWS Certificate Manager (ACM) and AWS Elastic Load Balancer (ELB), but it is not something that AWS performs automatically.
D. Creating TLS certificates for users' websites is a task that can be performed using AWS Certificate Manager (ACM), but it is not something that AWS performs automatically. Customers must request and configure TLS certificates for their websites.