Select ALL recognized methods of acquiring library materials.

### Why this is right - **Purchase** obtains materials through buying them. - **Gift** adds materials donated to the library. - **Exchange** obtains materials through an arrangement with another party. ### The concept These are acquisition methods. Subject searching is a way to find information, and authority control supports consistent catalog records. ### The other options - **Subject searching**: It is a search approach, not a way to obtain library stock. - **Authority control**: It maintains consistency in catalog records, not collection acquisition. ### Remember Acquisition methods bring materials into the collection.