In File Explorer of Windows 10, the keyboard shortcut 'Num Lock' + Asterisk sign (*) is used to ______.

Correct option is A

In Windows 10's File Explorer, pressing 'Num Lock' + Asterisk (*) expands and displays all subfolders under the selected folder. This shortcut is useful for quickly viewing the folder structure.
(b) Open the properties dialog box for the selected item: This is incorrect because the shortcut for opening properties is Alt + Enter, not Num Lock + Asterisk.
(c) Display the contents of the selected folder: This is incorrect because this action is typically done by clicking the folder or pressing Enter, not using Num Lock + Asterisk.
(d) Collapse the selected folder: This is incorrect because the shortcut for collapsing a folder is typically the Minus (-) key on the numeric keypad, not Num Lock + Asterisk.