If you're a business owner who wants to analyze how users arrive at your website and app, as well as the user journeys across both of these platforms, what should you use to generate insights?

Use Google Analytics 4 properties is correct because GA4 is designed to track and unify user interactions across both websites and mobile apps within a single property, providing insights into how users arrive, engage, and move between platforms. This event-based measurement model enables cross-platform analysis and user journey tracking, whereas Firebase focuses mainly on app analytics, Universal Analytics is limited in cross-platform capabilities, and Google Marketing Platform provides broader marketing tools rather than unified user journey reporting.