Choices: (A). Trace an l-bracket onto the inside of the book. Open the sacrificial book's back cover and use your tape measure to find the halfway point. (B). You might also consider buying digital paperbacks so you can create shelves that will all be created the same way (via combining other books you have available). Wrap masking tape around the front cover to give your book some heft. (C). You can also substitute a bookshelf storage container or individual display. Encourage the people in your home who sell books to try and put their books away electronically and store them in a safe, separate box so you don't have access to them. (D). Paint a label on the front of the book which says " invisible shelves. " the label should indicate the format of the information it contains.Choose from options above and answer: What most naturally follows?

How to create invisible shelves
Choose a suitable book that you won't want to read ever again.
This will become the " sacrificial " book that makes the shelf. Since it will be supporting other books, a large, hardcover book works best.
Answer:
(A).