Explanation:

The analogy given in the question is that window is to pane as a book is to something. The two words in the first part of the analogy are related as a window is made up of panes. Similarly, a book is made up of different components.

The correct answer is option 'D' which is "page". Here is why:

1. Relationship between a window and pane:

A window is made up of panes. A pane is a piece of glass that is fitted into a frame in a window or door. A window can have multiple panes.

2. Relationship between a book and page:

A book is made up of pages. A page is a sheet of paper in a book, magazine, or newspaper, typically with printed or written material on it. A book can have multiple pages.

3. Similarity between pane and page:

Just like a window is made up of multiple panes, a book is made up of multiple pages.

4. Alternative options and why they are incorrect:

a) Novel: A novel is a type of book, but not all books are novels. The analogy is not specific enough to suggest that the book in question is a novel.

b) Glass: Glass is a material that can be used to make panes, but it is not a component of a book.

c) Cover: A book cover is an important part of a book, but it is not analogous to a pane in a window. A book cover is more like the frame of a window.

Therefore, the correct answer is "page".