An ecommerce company runs its application on AWS. The application uses an Amazon Aurora PostgreSQL cluster in Multi-AZ mode for the database. During a recent promotional campaign, the application experienced heavy read and write load. Users experienced timeout issues when accessing the application. A solutions architect needs to make the application architecture more scalable and highly available with the LEAST downtime. Which solution will meet these requirements?

The correct solution addresses both scalability and high availability with minimal downtime. Adding additional reader instances to the Aurora cluster offloads read traffic from the primary instance, improving scalability and performance during heavy read loads. Creating an Amazon RDS Proxy target group provides connection pooling, reducing the overhead of establishing new database connections, and automatically routes connections to a healthy database instance during failovers, enhancing high availability with minimal application impact. Incorrect options: EventBridge and Lambda for logging state changes do not directly improve scalability or availability for application users. Adding reader nodes to fail over to is part of the solution, but not the complete answer. Zero-downtime restart (ZDR) is for maintenance, not for scaling read/write capacity or improving availability during heavy load. Database Activity Streams are for monitoring, not performance or availability. ElastiCache for Redis is a caching solution that can improve read performance but requires application changes to implement a write-around approach and doesn't directly address the Aurora cluster's read/write scalability or high availability for the primary instance.