The correct answer is .exe..exe is a common filename extension denoting an executable file (the main execution point of a computer program) for Microsoft Windows. A file extension or file name extension is the ending of a file that helps identify the type of file in operating systems, such as Microsoft Windows.In Microsoft Windows, the file name extension is a period that is often followed by three characters but may also be one, two, or four characters long.Additional InformationExtensionFormat.docMicrosoft Word document before Word 2007.pdfPortable Document Format file.textUnformatted text file.aacWindows audio file.emlEmail file created by Outlook Express, Windows Live Mail, and other programs..exeExecutable program file.jpg, jpegJoint Photographic Experts Group photo file.pngPortable Network Graphics File.ppsxMicrosoft PowePoint slide show.xlsxMicrosoft Excel Workbook after excel 2007.