A greeting card company recently advertised that customers could send cards to their favorite celebrities through the company's platform. Since the advertisement was published, the platform has received constant traffic from 10,000 unique users each second.
The platform runs on m5.xlarge Amazon EC2 instances behind an Application Load Balancer (ALB). The instances run in an Auto Scaling group and use a custom AMI that is based on Amazon Linux. The platform uses a highly available Amazon Aurora MySQL DB cluster that uses primary and reader endpoints. The platform also uses an Amazon ElastiCache for Redis cluster that uses its cluster endpoint.
The platform generates a new process for each customer and holds open database connections to MySQL for the duration of each customer's session. However, resource usage for the platform is low.
Many customers are reporting errors when they connect to the platform. Logs show that connections to the Aurora database are failing. Amazon CloudWatch metrics show that the CPU load is low across the platform and that connections to the platform are successful through the ALB.
Which solution will remediate the errors MOST cost-effectively?

A. Set up an Amazon CloudFront distribution. Set the ALB as the origin. Move all customer traffic to the CloudFront distribution endpoint.
B. Use Amazon RDS Proxy. Reconfigure the database connections to use the proxy.
C. Increase the number of reader nodes in the Aurora MySQL cluster.
D. Increase the number of nodes in the ElastiCache for Redis cluster.