Explanation

AWS Shield is the correct answer because it is AWS's managed Distributed Denial of Service (DDoS) protection service.

Service Breakdown:

1. AWS Shield:

   • Provides managed DDoS protection
   • Comes in two tiers:
     • AWS Shield Standard: Free, automatic protection for all AWS customers
     • AWS Shield Advanced: Paid service with additional features like 24/7 DDoS response team, cost protection, and advanced attack mitigation

2. Why other options are incorrect:

   • AWS Firewall Manager: A security management service that allows you to centrally configure and manage firewall rules across your AWS accounts and applications
   • Amazon GuardDuty: A threat detection service that continuously monitors for malicious activity and unauthorized behavior
   • Amazon Inspector: An automated security assessment service that helps improve the security and compliance of applications deployed on AWS

Key Features of AWS Shield:

• Always-on detection and automatic inline mitigations
• Integration with Amazon CloudFront, Amazon Route 53, and Elastic Load Balancing
• Real-time visibility into attacks via AWS WAF, Amazon CloudWatch, and AWS Management Console
• Protection against infrastructure layer (Layer 3/4) and application layer (Layer 7) attacks

AWS Shield is specifically designed to protect AWS applications from DDoS attacks, making it the appropriate choice for managed DDoS protection.