What is the main advantage of using AWS auto-scaling?

Correct answer: Automatically adjusts compute capacity based on demand to maintain performance and optimize costs

Option C is correct because AWS Auto Scaling monitors application demand and automatically adds or removes EC2 instances (and other resources) to maintain performance targets while avoiding over-provisioning, directly reducing costs during low-demand periods. Option A is incorrect because Auto Scaling has no relationship to storage; it manages compute capacity, and there is no AWS service that provides free unlimited storage. Option B is incorrect because Auto Scaling does not guarantee constant pricing; costs fluctuate with usage, though scaling down during low demand does optimize spend. Option D is incorrect because Auto Scaling complements, rather than replaces, monitoring; it relies on CloudWatch metrics and alarms to make scaling decisions, meaning monitoring becomes more important, not unnecessary.