In the following question find out the alternative which will replace the question mark.

letter : word :: page : ?

book

The correct answer is OPTION 2 - BOOK

The relationship in the analogy is based on parts and wholes:
 A letter is a part of a word.
 Similarly, a page is a part of a book.

Thus, the analogy "letter : word :: page : book" correctly reflects the part-to-whole relationship.