A company migrating an on-premises application to Azure wants the app to remain accessible even if a single physical server or a small group of servers fails. Which cloud computing benefit primarily addresses this concern?

High Availability is the correct answer because it ensures an application remains operational and accessible despite failures in underlying infrastructure, such as physical servers. This is achieved through redundant systems, failover mechanisms, and distributed resources. Agility refers to the ability to rapidly develop, test, and deploy applications, which doesn't directly address server failures. Scalability is the ability to increase or decrease resources to meet demand, but it doesn't inherently guarantee continuous operation during a failure. Cost-Effectiveness relates to optimizing expenses, which is a benefit of cloud computing but not the primary solution for ensuring application uptime during server outages.