The correct answer is C. Book
Explanation:
A guide word is a word that is at placed the top of the page in a dictionary or similar document containing alphabetically organized words that show the first or the last word in a page which facilitates the process of looking for a word in documents such as dictionaries or glossaries. This means if the guide words are bone and bow the page of the dictionary, glossary or reference document will contain words that are between "bone" and "bow" in terms of alphabetical organization. Including words such as book, boot, boost, born or boss. Thus, from the options the only word that would appear between the guide words bone and bow is book as these words are the first word and the last word that appear in a list of words alphabetically organized and the word "book" is after "bone", but before "boss" in terms of alphabetically order which means "book" will appear between these two words in a dictionary or glossary.
