Amazon Web Services (AWS)

Answer - B.

The AWS Documentation mentions the following:

Amazon Simple Notification Service (Amazon SNS) is a web service that enables applications, end-users, and devices to send and receive notifications from the cloud instantly.

For more information on AWS SNS, please visit the URL:

The correct answer is B. AWS SNS.

AWS SNS (Simple Notification Service) is a fully managed messaging service that enables you to send notifications from the cloud. It is designed to make it easy to send messages to a large number of subscribers in real-time, such as to mobile devices, email addresses, and HTTP endpoints.

In this scenario, the EC2 instance hosting the web application can use AWS SNS to send notifications based on events. For example, if the web application detects a critical error or an important event, it can publish a message to an SNS topic. Subscribers who have subscribed to that topic will receive the message, which could be sent via SMS, email, or other channels.

AWS SES (Simple Email Service) is also a messaging service, but it is designed specifically for sending emails. It can be used to send emails programmatically, such as from an EC2 instance or a Lambda function. However, it is not the best choice for sending notifications based on events since it doesn't support other notification channels like SMS or mobile push notifications.

AWS SQS (Simple Queue Service) is a fully managed message queuing service that enables you to decouple and scale microservices, distributed systems, and serverless applications. It is designed to buffer messages between distributed application components, so they can process them asynchronously. However, it doesn't provide notification capabilities like SNS does.

Finally, AWS EC2 (Elastic Compute Cloud) is a web service that provides scalable computing capacity in the cloud. It is not a messaging or notification service and doesn't offer any direct assistance for sending notifications.