Correct Answer: (b) Ctrl+Z
Solution:In Windows operating system, the shortcut key to undo a task is Ctrl+Z.
Ctrl+C is used to copy the selected text, image or any item from the clipboard.
To repeat something simple, such as a paste operation, press Ctrl + Y or F4 ( If F4 doesn't seem to work, you may need to press the F-Lock key or Fn Key, then F4 ) Control, and Ctrl+A is a keyboard shortcut most often used to select all text, files, pictures, or other objects while in a graphical user environment.