Which tool gives detailed insights into application performance and failures across multiple Azure services?

Azure Application Insights is the correct answer because it's an Application Performance Management (APM) service that monitors live web applications. It automatically detects performance anomalies and includes powerful analytics tools to help diagnose issues and understand what users actually do with your app. Azure Advisor provides recommendations for optimizing Azure resources for cost, performance, reliability, operational excellence, and security, but it doesn't offer detailed application performance monitoring. Azure Cost Management helps you analyze and manage your Azure spending, not application performance. Azure Monitor collects and analyzes telemetry from your Azure resources, but Application Insights is a specialized component of Azure Monitor specifically focused on application performance and failures.