AWS Compute Optimizer is the correct service that provides rightsizing recommendations for Amazon EC2 instances based on historical workload usage data. It analyzes resource utilization metrics and suggests optimal instance types to help reduce costs and improve performance.

Key features of AWS Compute Optimizer:

• Analyzes historical utilization metrics for EC2 instances
• Provides rightsizing recommendations to match workload requirements
• Helps optimize costs by suggesting appropriate instance types
• Identifies opportunities to scale down over-provisioned instances

Other options explained:

• AWS Pricing Calculator: Used for estimating AWS service costs, not for rightsizing recommendations
• AWS App Runner: A fully managed service for building and running containerized web applications
• AWS Systems Manager: A management service for operational data and automation tasks, not specifically for rightsizing recommendations