Amazon SQS is a fully managed message queuing service that enables you to decouple and scale microservices, distributed systems, and serverless applications.Here we require a notification service not a message queue service like SQS.

SWF makes it easy to build applications that use Amazon's cloud to coordinate work across distributed components. Amazon SWF gives you full control over implementing tasks and coordinating them without worrying about underlying complexities such as tracking their progress and maintaining their state.
Therefore it is a workflow orchestration service and it is not used for publishing messages to mobile app users.

Amazon SNS is a fully managed messaging service for both application-to-application (A2A) and application-to-person (A2P) communication. With Amazon SNS, you have the ability to send push notification messages directly to apps on mobile devices. Push notification messages sent to a mobile endpoint can appear in the mobile app as message alerts, badge updates, or even sound alerts. You send push notification messages to both mobile devices and desktops using supported push notification services.

Amazon CloudWatch Events delivers a near real-time stream of system events that describe changes in Amazon Web Services (AWS) resources. Hence, CloudWatch Events will not be able to send notifications to mobile app users.

NEW SERVICE ALERT: Amazon EventBridge is the preferred way to manage your events. CloudWatch Events and EventBridge are the same underlying service and API, but EventBridge provides more features. Changes you make in either CloudWatch or EventBridge will appear in each console.

1." push notification" which redirects us to Amazon SNS as it is a basic notification service used to send push notification messages to both mobile devices and desktops.

This service alerts you about events happening in your AWS resources, it does not allow you to run scripts on EC2 instances.

EC2 Metadata is data about your instance that you can use to configure or manage the running instance.

Run command does allow the running of scripts on EC2 instances at scale. However, this is not the simplest method of achieving this objective as we’re only dealing with a single instance.

When you launch an instance in Amazon EC2, you have the option of passing EC2 User Data to the instance that can be used to perform common automated configuration tasks and even run scripts after the instance starts.You can pass two types of user data to Amazon EC2: shell scripts and cloud-init directives. You can also pass this data into the launch wizard as plain text, as a file (this is useful for launching instances using the command line tools), or as base64-encoded text (for API calls).

1." run a script when the instance is being launched." which redirect us to Run Command & EC2 User Data.

2." An Amazon EC2 instance" & "SIMPLEST method of running the script" which clearly redirect us to EC2 User Data as the run command is used for multiple instances, while User data is used for single instance & EC2 User data is simpler.

This service is used to store secure secrets, not to access vulnerabilities.

This service is used to protect from distributed denial of service (DDoS) attacks.

Amazon Inspector is an automated security assessment service that helps improve the security and compliance of applications deployed on AWS. Amazon Inspector automatically assesses applications for exposure, vulnerabilities, and deviations from best practices. After performing an assessment, Amazon Inspector produces a detailed list of security findings prioritized by level of severity. These findings can be reviewed directly or as part of detailed assessment reports which are available via the Amazon Inspector console or API.

This is a web application firewall that gives you control over how traffic reaches your applications by enabling you to create security rules that block common attack patterns, such as SQL injection or cross-site scripting, and rules that filter out specific traffic patterns you define.

1."automatically assess applications for exposure, vulnerabilities, and deviations from best practices" which redirect us directly to Amazon Inspector as it is only assessment service in given options.