Which solution will resolve this issue with the LEAST development effort?

Explanations:

DynamoDB Accelerator (DAX) is a fully managed, in-memory caching service for DynamoDB that can significantly speed up read operations. It provides microsecond response times for read-heavy workloads, reducing the strain on the main DynamoDB table and allowing other applications to access the data without disruption. This solution requires minimal development effort as it integrates easily with existing DynamoDB applications without needing to modify data access patterns.

Amazon CloudFront is a content delivery network (CDN) that caches content at edge locations, but it is not directly designed for caching DynamoDB queries or data. While it can speed up the delivery of static assets, it won’t address the read capacity issues on DynamoDB effectively. Additionally, setting up CloudFront would involve more complexity and development effort compared to other solutions.

Creating a local secondary index (LSI) allows for different query patterns and can optimize certain read operations, but it does not alleviate the overall read capacity limits of the primary table. Implementing LSIs would require changes to the data model and may not provide immediate relief to the read capacity issues, thus involving more development effort.

Amazon ElastiCache is an in-memory caching service that could be used to offload read requests from DynamoDB, but implementing it would require significant changes in application architecture and data access patterns. It involves more development effort than DAX, as it requires managing cache consistency and potentially altering how the application reads data.