The library's reference collection will not be as complete or up-to-date as in the past.
This is the best option because the conclusion is that the library will not be able to purchase as many new books and other materials. The best option directly relates to this conclusion of less books. In the correct option, the collection not being as complete or up-to-date is due to fewer books being purchased. The second option doesn't support the conclusion because it talks about hours and programs - not books. The third option can relate to books, but it is not as explicit as option 1. The last option also doesn't make a direct connection between the lack of funding to purchase books and the result.
