Which combination of actions should the solutions architect take to accomplish this?

Explanations:

Migrating the PostgreSQL database to Amazon Aurora can improve scalability, availability, and performance. Aurora is a managed database service that offers automated backups, replication, and failover, which reduces operational overhead and supports growth without the need for extensive capacity planning.

Migrating the web application to Amazon EC2 instances would still require the company to manage the underlying infrastructure, including scaling and maintenance. This option does not significantly reduce operational overhead compared to the current on-premises setup.

Setting up an Amazon CloudFront distribution can improve content delivery speed and reduce latency for users, but it does not address the underlying infrastructure issues or operational overhead associated with maintaining the web application and database.

Implementing Amazon ElastiCache can help improve application performance by caching frequently accessed data, but it does not directly address the operational overhead of managing the infrastructure or the challenges of capacity planning.

Migrating the web application to AWS Fargate with Amazon Elastic Container Service (Amazon ECS) allows for a serverless container management experience. Fargate eliminates the need to manage the underlying EC2 instances, significantly reducing operational overhead and enabling the company to scale more easily in response to demand.