Which of the following aids in efficient retrieval of information in a library?

The use of an index is vital in facilitating efficient retrieval of information in a library. An index serves as a systematic guide that lists subjects, names, and topics in a structured format, often accompanied by page numbers or locations where the referenced information can be found within a larger work, such as a book or database. This helps users quickly locate specific information without needing to read through entire documents or materials.

While dictionaries, thesauruses, and encyclopedias provide valuable information and definitions, they do not serve the primary function of indexing materials. A dictionary offers definitions and meanings of words, a thesaurus lists synonyms and antonyms to improve vocabulary, and an encyclopedia provides comprehensive overviews of topics. Each of these resources is beneficial for learning and understanding, but an index is specifically designed to streamline the research process by pointing to precise locations of content within broader texts.