Microsoft Certified: Azure Fundamentals (AZ-900) Practice Exam

The correct choice is Azure Application Gateway because it is specifically designed to manage and route traffic to web applications. It serves as a web traffic load balancer, providing various features such as SSL termination, session affinity, and URL-based routing. This enables efficient distribution of incoming web traffic across multiple servers, enhancing the performance and reliability of applications.

Azure Application Gateway also includes advanced capabilities like Web Application Firewall (WAF) to help protect applications from common web vulnerabilities. Therefore, it is optimally equipped for handling traffic management in the context of web applications.

In contrast, the other options do not serve the same purpose. An Availability Set is focused on ensuring high availability and redundancy for virtual machines by grouping them in a way that minimizes downtime. A Scale Set allows for automatic scaling of applications and managing large numbers of identical virtual machines, but it does not directly manage incoming traffic to those applications. A Virtual Network Gateway facilitates communication between Azure Virtual Networks and on-premises networks but is not designed for managing traffic specifically to web applications.