Concept:Keyboard shortcuts for formatting text in Word mostly use the Ctrl key together with a letter key.
Explanation:To underline selected text, press and hold the Control key (Ctrl) and then press the letter U.
The letter U represents Underline, making it easy to remember.
In Microsoft Word, the correct shortcut is Ctrl + U.
Other common formatting shortcuts include Ctrl + B for bold and Ctrl + I for italics.
Options Alt, Tab, or Shift combined with U do not give the underline effect in Word.
Therefore, the correct choice is the one that uses Ctrl with U.
Answer:C. Ctrl + U.