A flash-sale API uses Lambda and RDS for PostgreSQL. Sudden Lambda concurrency creates many short-lived database connections, exhausting the database's connection limit. The company wants a managed connection-pooling layer without changing the database engine. Which service should it add?

1. A Network Load Balancer that creates a new database backend session for every request.
2. An RDS read replica and direct all writes to that replica.
3. Amazon RDS Proxy, and have the Lambda functions connect through the proxy endpoint.
4. An S3 gateway endpoint between Lambda and PostgreSQL.