Answer: D
Correct answer: It applies the Normal style to the selected paragraph
Ctrl + Shift + N applies the Normal style, stripping paragraph-level formatting back to the document default. It is the fastest way to undo a tangle of manual formatting. Its companion is Ctrl + Spacebar, which removes character formatting - bold, italic, colour, size - while leaving the paragraph style intact. Between them the two clear almost any formatting problem. The heading shortcuts belong with them: Ctrl + Alt + 1, 2 and 3 apply Heading 1, 2 and 3, which is much faster than choosing from the Styles gallery and matters because those styles drive the table of contents and the Navigation pane. Ctrl + N, without Shift, creates a new document - which is the second option and the usual confusion. Note that Normal here is a paragraph style, distinct from the Normal.dotm template that supplies the defaults for every new document.