You support a high-traffic web application that runs on Google Cloud Platform (GCP). You need to measure application reliability from a user perspective without making any engineering changes to it. What should you do? (Choose two.)

A. Review current application metrics and add new ones as needed. B. Modify the code to capture additional information for user interaction. C. Analyze the web proxy logs only and capture response time of each request. D. Create new synthetic clients to simulate a user journey using the application. E. Use current and historic Request Logs to trace customer interaction with the application.