Amazon Web Services Updated CLF-C02 Exam Questions and Answers by jorge

 The correct answers are A and C because Amazon EC2 Auto Scaling and resources that are distributed across multiple Availability Zones are AWS services and features that will improve availability and reduce the impact of failures for the web application. Amazon EC2 Auto Scaling is a service that enables users to automatically adjust the number of Amazon EC2 instances in response to changes in demand or performance. Amazon EC2 Auto Scaling helps users to maintain optimal availability and performance of their applications by adding or removing instances as needed. Resources that are distributed across multiple Availability Zones are AWS features that enable users to increase the fault tolerance and resilience of their applications. Availability Zones are isolated locations within an AWS Region that have independent power, cooling, and networking. Users can launch their resources, such as Amazon EC2 instances, in multiple Availability Zones to protect their applications from the failure of a single location. The other options are incorrect because they are not AWS services and features that will improve availability and reduce the impact of failures for the web application. VPC subnet ACLs are AWS features that enable users to control the inbound and outbound traffic to and from their subnets within a VPC. VPC subnet ACLs do not check the health of a service, but rather filter the network traffic based on rules. Configuration of AWS Server Migration Service (AWS SMS) is an AWS service that enables users to migrate their on-premises servers to AWS. Configuration of AWS SMS does not help to move the Amazon EC2 instances to a different AWS Region, but rather to migrate the servers from the source environment to AWS. Resources that are distributed across multiple AWS points of presence are AWS features that enable users to deliver content to their end users with low latency and high performance. AWS points of presence are edge locations that are part of the AWS Global Infrastructure. Users can use services such as Amazon CloudFront and AWS Global Accelerator to distribute their content across multiple AWS points of presence. Reference: Amazon EC2 Auto Scaling, [Regions, Availability Zones, and Local Zones]

 The correct answer is C because Amazon Cognito provides identity federation and user authentication for web and mobile applications. Amazon Cognito allows users to sign in with their social media, email, or online shopping accounts. The other options are incorrect because they do not provide identity federation or user authentication. AWS IAM Identity Center (AWS Single Sign-On) is a service that enables users to access multiple AWS accounts and applications with a single sign-on experience. AWS Config is a service that enables users to assess, audit, and evaluate the configurations of their AWS resources. AWS Identity and Access Management (IAM) is a service that enables users to manage access to AWS resources using users, groups, roles, and policies. Reference: Amazon Cognito FAQs

Cost optimization is the pillar of the AWS Well-Architected Framework that focuses on the return on investment of moving into the AWS Cloud. Cost optimization means that users can achieve the desired business outcomes at the lowest possible price point, while maintaining high performance and reliability. Cost optimization can be achieved by using various AWS features and best practices, such as pay-as-you-go pricing, right-sizing, elasticity, reserved instances, spot instances, cost allocation tags, cost and usage reports, and AWS Trusted Advisor. [AWS Well-Architected Framework] AWS Certified Cloud Practitioner - aws.amazon.com

Availability Zones are physically separate locations within an AWS Region that are engineered to be isolated from failures. Each Availability Zone has independent power, cooling, and physical security, and is connected to other Availability Zones in the same Region by a low-latency network. Therefore, the correct answers are A and D. You can learn more about Availability Zones and their characteristics from this page.