The correct answer is C because learning to improve from operational failures is a recommended design principle of the AWS Well-Architected Framework. The AWS Well-Architected Framework is a set of best practices and guidelines for designing and operating reliable, secure, efficient, and cost-effective systems in the cloud. The AWS Well-Architected Framework consists of five pillars: operational excellence, security, reliability, performance efficiency, and cost optimization. Each pillar has a set of design principles that describe the characteristics of a well-architected system. Learning to improve from operational failures is a design principle of the operational excellence pillar, which focuses on running and monitoring systems to deliver business value and continually improve supporting processes and procedures. The other options are incorrect because they are not recommended design principles of the AWS Well-Architected Framework. Reducing downtime by making infrastructure changes infrequently and in large increments is not a design principle of the AWS Well-Architected Framework, but rather a source of risk and inefficiency. A well-architected system should implement changes frequently and in small increments to minimize the impact and scope of failures. Investing the time to configure infrastructure manually is not a design principle of the AWS Well-Architected Framework, but rather a source of human error and inconsistency. A well-architected system should automate manual tasks to improve the speed and accuracy of operations. Using monolithic application design for centralization is not a design principle of the AWS Well-Architected Framework, but rather a source of complexity and rigidity. A well-architected system should use loosely coupled and distributed components to enable scalability and resilience. Reference: [AWS Well-Architected Framework]