Which solution meets these requirements?
Enable Amazon GuardDuty on the account.
Enable Amazon Inspector on the EC2 instances.
Enable AWS Shield and assign Amazon Route 53 to it.
Enable AWS Shield Advanced and assign the ELB to it.
Explanations:
Amazon GuardDuty is a threat detection service that monitors for malicious activity but does not specifically protect against DDoS attacks.
Amazon Inspector is a security assessment service for EC2 instances to improve security posture but does not provide DDoS protection.
While AWS Shield provides DDoS protection, assigning Amazon Route 53 (a DNS service) to it does not adequately protect the application behind the ELB.
AWS Shield Advanced provides enhanced DDoS protection specifically for applications, and assigning it to the Elastic Load Balancer directly protects the app.