The correct answer is B, AWS Business Support. This plan is the most cost-effective option that includes access to the full set of AWS Trusted Advisor best practice checks. AWS Trusted Advisor provides valuable insights and recommendations to help optimize your AWS infrastructure for cost, performance, security, and fault tolerance. While AWS Basic Support does include some AWS Trusted Advisor checks, it only includes the core checks, not the full set. AWS Business Support is the next tier up and includes all checks, making it the least expensive plan with access to the complete set of checks.