Which campaign objective can advertisers use to increase mobile app installs?

The App Installs objective is specifically designed to drive users to download and install a mobile application. This objective optimizes ad delivery to reach users most likely to perform an app install, making it the most effective choice for this goal. While Conversions could technically track app installs as a conversion event, it's a broader objective and less optimized for this specific action than App Installs. Catalog Sales is for promoting products from a catalog, and Traffic aims to send users to a website or landing page, neither of which directly optimizes for app installations.