-- in the wheelhouse, inside the book titled "Captain's Log." Take a picture of this page, because you can't take the book.
Magnus's note about sails tells you that from tallest to shortest, the masts are the mainmast, the foremast, the mizzenmast, and the jiggermast, and the bowsprit is the spar that sticks out of the bow.
That means the masts in this display, from left to right, are the bowsprit, the foremast, the mainmast, the mizzenmast, and the jiggermast.
The sails themselves -- well, read through Magnus's list; it's complicated, but straightforward. Sails are named according to what mast they're attached to and how close they are to the deck.
If you're getting frustrated, here are the answers:
What you get when you complete this quiz is a page defining a whole bunch of nautical terms. You can actually live a long and happy life without knowing this (though you may need to complete the puzzle to move the action forward), but you might want to take a snapshot of it anyway, since later in the game you'll come across those terms again.