You must expose a public API that handles authentication, enforces quotas, and reports API metrics. Which product should you use?

Cloud Endpoints is the correct choice because it's specifically designed to manage, monitor, and secure APIs. It integrates with an API gateway to handle authentication (e.g., using API keys or Firebase Auth), enforce quotas, and provide detailed API metrics and logging. App Engine is a platform for building and hosting web applications and APIs, but it doesn't natively provide the API management features like quota enforcement or detailed metrics that Cloud Endpoints offers. Identity-Aware Proxy (IAP) secures access to applications running on Google Cloud, but it's primarily for identity-based access control to internal resources, not for public API management with quotas and metrics. GKE Ingress for HTTP(S) Load Balancing is used for routing external HTTP(S) traffic to services within a GKE cluster; while it can handle basic authentication and SSL, it lacks the comprehensive API management capabilities of Cloud Endpoints.