The correct answer is: B. Ctrl + 0
Ctrl + 0 is the keyboard shortcut for resetting the zoom level in Google Chrome to the default value. This is useful if you have accidentally zoomed in or out of a page and want to return to the original view.
The other options are not correct. Ctrl + R is the keyboard shortcut for refreshing a page. Ctrl + 9 is the keyboard shortcut for going to the ninth tab in your browser. Ctrl + D is the keyboard shortcut for adding a page to your bookmarks.
I hope this helps!