A. A unique identifier for each cell in the spreadsheet
B. A function used to format cells
C. A hyperlink to another cell or document
D. A shortcut key for accessing cells

Solution

A. A unique identifier for each cell in the spreadsheet

Explanation

A cell reference in LibreOffice Calc is a unique identifier for each cell in the spreadsheet, consisting of the column letter and row number (e.g., A1, B2, C3).