Computer Science

Facebook was launched in 2004 by Mark Zuckerberg and his college roommates. This is a well-documented fact in the history of social media platforms.

A bit is the basic unit of digital information and represents a binary value of either 0 or 1. It is not equal to any decimal number like 0.125, 0.150, or 0.12, so the correct answer is 'None of these'.

The welcome screen in most operating systems displays the names of all user accounts available on the computer, allowing users to select their profile to log in. This matches option B, making it the correct answer.

The correct HTML tag to underline text is <u>. Since none of the given options (B, C, D) represent the <u> tag, the correct answer is 'None of these'.

Ctrl + Y is the standard keyboard shortcut for the 'Redo' action, which reverses the last undo operation. This is distinct from Ctrl + Z, which is used for 'Undo'.

In computer science, 'PB' commonly stands for 'Petabyte,' which is a unit of digital information storage equal to 1,024 terabytes. The other options are incorrect in this context.

The keys labeled F1 through F12 on a keyboard are known as function keys because they perform specific functions depending on the software or operating system in use.

IBM stands for International Business Machines, which is the correct full form of the acronym IBM.

CD-ROM stands for Compact Disc Read-Only Memory, which means data on the disc can only be read and not written or erased.

HTML stands for Hypertext Markup Language, which is the standard language used to create and design web pages. This is a well-known and established fact in computer science.