In numeric storage, a cross-reference is filed in the a. alphabetic index. b. accession log. c. numbered file. d. Both a and b

A- Alphabetic index

Step-by-step explanation:

An alphabetic index is a reference to a numeric file. It is alphabetically organized to allow easy location when the assigned number is not known.

An alphabetic index is important in numeric storage because, with it, rapid retrieval of a record is possible. The index uses names and subjects to code for a numeric record. These subjects serve as codes for either each file or a group of files, sorting the information base in an organized format. Names or just single letters could be used in the index as the code for the numeric record strorage.

When trying to locate a file, the alphabetic code used for the numeric information or the group of files, is the first source assessed. The alphabetic index of records is best kept in a single location to avoid a search in multiple locations, complicating the retrieval of a record.The index should be kept valid by ensuring it is up-to-date and is accurate.