Amazon S3 Glacier is the correct answer because it is specifically designed for data archiving and long-term backup at very low costs. It supports retrieval times ranging from a few minutes to several hours, which aligns with the company's acceptable retrieval time frame. Amazon S3 Glacier provides high durability and availability, which is essential for storing important financial records.

Amazon S3 Standard, while also highly durable and available, is more expensive for storage and is typically used for frequently accessed data. Amazon EBS is designed for block-level storage volumes for EC2 instances and is not suited for archiving. Amazon RDS is a managed relational database service and is not used for archiving files.