The correct answer is B and C. EC2 Amazon Machine Images (AMIs) and Amazon Elastic Block Store (Amazon EBS) snapshots are two AWS services that provide disaster recovery solutions for Amazon EC2 instances.
EC2 AMIs are preconfigured templates that contain the software configuration and data required to launch an EC2 instance. You can create AMIs from your running EC2 instances and use them to launch new instances in the same or different AWS Regions. This way, you can quickly recover your EC2 instances in case of a disaster that affects your primary Region or Availability Zone1.
Amazon EBS snapshots are incremental backups of your Amazon EBS volumes. You can create snapshots of your volumes and store them in Amazon S3, which is a highly durable and scalable storage service. You can use snapshots to restore your volumes to a previous point in time or to create new volumes from snapshots. Snapshots can also be copied across AWS Regions, enabling you to recover your data in another Region in case of a disaster2.
The other options are not directly related to disaster recovery for EC2 instances:
EC2 Reserved Instances are a pricing model that allows you to reserve EC2 capacity for a specific period of time and receive a discount on the hourly charge. Reserved Instances do not provide any disaster recovery benefits, as they are only a billing option3.
AWS Shield is a managed service that protects your AWS resources from distributed denial-of-service (DDoS) attacks. AWS Shield provides basic protection for all AWS customers at no additional charge, and advanced protection for customers who need higher levels of detection and mitigation. AWS Shield does not provide any disaster recovery benefits, as it is only a security service4.
Amazon GuardDuty is a threat detection service that monitors your AWS account and workloads for malicious or unauthorized activity. Amazon GuardDuty analyzes various data sources, such as AWS CloudTrail, Amazon VPC Flow Logs, and DNS logs, to identify potential threats and alert you via Amazon CloudWatch Events or AWS Lambda. Amazon GuardDuty does not provide any disaster recovery benefits, as it is only a monitoring service5.
