Files created with Lotus 1-2-3 have an extension?

The correct answer is 123 because native spreadsheet documents created within later versions of the classic Lotus 1-2-3 productivity suite utilize the default .123 filename suffix.

• Step 1 (Software Context): Lotus 1-2-3 was a highly influential spreadsheet application that dominated personal computing throughout the 1980s. While legacy versions primarily saved work using the .WKS or .WK1 file formats, newer iterations adopted the namesake .123 format.


• Step 2 (Function): Filename extensions tell the desktop operating system which specific application executable to launch when a user tries to load a file.


• Incorrect Options:
  
  
  
  • DOC is incorrect because it is the classic legacy filename extension reserved for document files processed in Microsoft Word.
  
  
  • WK1 is incorrect because although it was widely used by early versions of Lotus 1-2-3, the software's direct signature extension is .123.
  
  
  • XLS is incorrect because it designates the native binary spreadsheet file layout belonging strictly to Microsoft Excel.