Comprehensive and Detailed Explanation From Exact Extract:

AWS CodeDeploy supports deployment of both Lambda functions and ECS services with native integration.

It provides deployment strategies such as canary deployments for Lambda and blue/green deployments for ECS, which minimize downtime and risk.

CodeDeploy automates the deployment process, which reduces manual effort and improves consistency.

AWS Systems Manager Parameter Store is a simple, managed solution for storing configuration data securely and at scale.

Option A uses CloudFormation stack updates with resource replacement, which can cause downtime and is less flexible for minimizing downtime compared to CodeDeploy’s deployment strategies.

Option C adds unnecessary orchestration complexity with Step Functions and cross-region deployments, increasing deployment effort.

Option D’s all-at-once deployments for Lambda and rolling updates for ECS do not minimize downtime as effectively as canary and blue/green strategies.Hence, option B meets the requirement with the least deployment effort and maximizes automation and availability.

Reference from AWS Official Documentation:

Deploying Lambda Functions with CodeDeploy:"AWS CodeDeploy supports canary and linear deployment strategies for AWS Lambda functions to reduce deployment risk."(CodeDeploy Lambda Deployment)

Deploying ECS Services with CodeDeploy Blue/Green:"CodeDeploy supports blue/green deployments for ECS to minimize downtime during service updates."(CodeDeploy ECS Blue/Green)

AWS Systems Manager Parameter Store:"Parameter Store provides secure, hierarchical storage for configuration data management."(Systems Manager Parameter Store)