Which of the following is an application software ?

Application software is a program or a group of programs designed for the end-users. It is a term that is used for software created for a specific purpose. In short, it is called an App.

MS - Word:

• MS - Word or Microsoft Word is an application software developed by the company Microsoft.
• It is a popular word processing program used for creating documents such as brochures, tests, quizzes, letters, student's homework assignments, etc.
• There are a number of simple and useful features available in MS - Word that make it easier for work and study. 

Therefore, MS - Word is application software.

Android:

• Android is a mobile operating system developed by Google.
• It is based on a modified version of the Linux kernel and other open-source software that was designed primarily for touchscreen mobile devices such as smartphones and tablets.
• The initial release date of Android was 23 September 2008.

iOS:

• iOS is the world's most advanced mobile operating system developed by Apple Inc. exclusively for its hardware. 
• It is the operating system that runs many of the company's mobile devices like iPhone, iPad, iPod, etc.
• The initial release date of Apple iOS was 29 June 2007.

Linux:

• Linux is a tried-and-true open-source Unix-like operating system released for computers on September 17, 1991.
• But its use has expanded to other systems like cars, phones, web servers, and recently to networking gears.
• Linux has a reputation of being fast and smooth as compared to the Windows OS.