Explanation:

Answer : c . System

The operating system is the most common type of System Software.  There are mainly two type of softwares

1. System Software A system software aids the user and the hardware to function and interact with each other. Basically, it is a software to manage computer hardware behavior so as to provide basic functionalities that are required by the user. 

Some common system software examples are:

Operating systems: lAndroid , CentOS , iOS , Linux , Mac OS , MS Windows , Ubuntu , Unix ,

Device Drivers:   OS Driver , Display Drivers , Motherboard Drivers , Printer Drivers , ROM Drivers , Sound card Driver, USB Drivers, VGA Drivers , Virtual Device Drivers

Firmware: BIOS , Computer Peripherals , Consumer Applications, Embedded Systems, UEFI

Programming Language Translators: Interpreter, Compiler and Assemblers.

2. Application software. also known as end-user programs or productivity programs are software that helps the user in completing tasks such as doing online research, jotting down notes, setting an alarm, designing graphics, keeping an account log, doing calculations or even playing games. 

Word Processors:  Abiword , Apple iWork- Pages , Corel WordPerfect , Google Docs , MS Word

Database Software:  Clipper , dBase , FileMaker , FoxPro , MS Access , MySQL

Multimedia Software:  Adobe Photoshop, Inkscape , Media Monkey, Picasa, VLC Media Player , Windows Media Player , Windows Movie Make

Web Browsers :  Delta Drawing , GCompris , Jumpstart titles , KidPix , MindPlay, Tux Paint