
Explanation:
Box 1: Basic
Basic load balancer supports Virtual machines in a single availability set or virtual machine scale set.
https://learn.microsoft.com/en-us/azure/load-balancer/skus
Box 2: Gateway
Gateway Load Balancer is a SKU of the Azure Load Balancer portfolio catered for high performance and high availability scenarios with third-party Network Virtual Appliances (NVAs).
With the capabilities of Gateway Load Balancer, you can easily deploy, scale, and manage NVAs.
https://learn.microsoft.com/en-ie/azure/load-balancer/gateway-overview