Exam AWS Certified Cloud Practitioner topic 1 question 413 discussion

A. Use an Auto Scaling group to scale resources in and out based on demand. The most cost-effective way to manage the resources while maintaining fault tolerance is to use an Auto Scaling group. This will automatically scale the number of Amazon EC2 instances up or down based on demand. B. Purchase Reserved Instances to ensure peak capacity at all times: This approach will ensure the company has the resources it needs to handle the traffic demand, but it is not cost-effective as it would require purchasing capacity for the entire day, even if it is not needed. C. Write a cron job to stop the EC2 instances when the traffic demand is low: This approach will save costs, but it would not ensure the availability and fault tolerance that the company requires. D. Write a script to vertically scale the EC2 instances during peak traffic demand: This approach will require continuous management and monitoring of the instances, and it is also not cost-effective, as it would require purchasing more resources than necessary.

A. Use an Auto Scaling group to scale resources in and out based on demand. https://docs.aws.amazon.com/autoscaling/ec2/userguide/auto-scaling-groups.html

A is the answer.

A. Use an Auto Scaling group to scale resources in and out based on demand. An Auto Scaling group is a useful tool for managing EC2 instances and other resources in a cost-effective and fault-tolerant way. By using an Auto Scaling group, you can automatically scale your resources in and out based on demand, ensuring that you have the capacity you need when you need it, and reducing costs when demand is low.

Can B (RI) do that since its about cost effective?