The correct answer is iOS.Operating System(OS)It is a System software that manages computer hardware, software resources and provides common services for computer programs.For hardware functions such as input and output and memory allocation, the operating system acts as an intermediary between programs and the computer hardware, although the application code is usually executed directly by the hardware and frequently makes system calls to an OS.Some operating systems require installation or may come pre-installed with purchased computers whereas others may run directly from media or flash memory.iOS?iOS is a mobile operating system created and developed by Apple Inc. exclusively for its hardware.It is the operating system that powers many of the company's mobile devices including the iPhone and iPod Touch, etc.It is the world's second-most widely installed mobile operating system, after Android.Additional Information AndroidAndroid is a mobile operating system based on a modified version of the Linux kernel and other open-source software, designed primarily for touch screens mobile devices such as smartphones and tablets.Android is developed by a consortium of developers known as the Open Handset Alliance and commercially sponsored by Google.Android KitKat is the eleventh version of android OS for mobiles.LTE?In telecommunication, Long-Term Evolution(LTE) is a standard for wireless broadband communication for mobile devices and data terminals, based on GSM/EDGE and UMTS/HSPA technologies.It increases the capacity and speed using a different radio interface together with core network improvements.