A user wants a phone with an operating system that is highly customizable. Which of the following operating systems will a technician MOST likely recommend?

Windows Mobile is a discontinued Microsoft platform that was relatively closed and offered limited customization compared to Android.

Android is built on the Linux kernel and released under the Android Open Source Project (AOSP), which allows manufacturers, developers, and users to modify the UI, install custom ROMs, sideload applications, and alter system-level behavior - a degree of customization not available on any other mainstream mobile platform.

Fire OS is Amazon's fork of Android locked to the Amazon ecosystem; it restricts access to Google Play and core Android customization options.

iOS is Apple's closed-source operating system with strict sandboxing, no official support for sideloading, and no ability to modify the OS without jailbreaking.