Answer:
(A) If a book was published in the past 150 years and is historically insignificant, it will probably deteriorate completely.
Step-by-step explanation:
This is the overall idea of the passage. Initially, the author explains how these books deteriorate themselves and then explains how this can be avoided. Finally, he/she presents the idea that there are techniques to prevent some books from completely deteriorating, but the process of deacidification will only be implemented to books which have historical significance.