As a system operations resource your focus is to make the best decision within the AWS infrastructure. You are tasked with managing AWS resources, such as EC2 instance types, geographic Regions, VPC management, and capacity planning and forecasting. Which option is a key cost-effective resource discussed in the Cost Optimization pillar of the AWS Well-Architected Framework? A) Right size B) Appropriate provisioning C) Limiting Regions D) Using Reserved Instances only