Apa ekstensi file default untuk dokumen Excel? Select one: a. polf D. pptx c. choir

The question seems to have a mistake as none of the provided options are correct. The correct answer should be '.xls' or '.xlsx'.

The question is asking about the default file extension for Excel documents. Excel, a product of Microsoft, primarily uses '.xls' or '.xlsx' as its default file extensions. The '.xls' is used for Excel 2003 and earlier versions, while '.xlsx' is used for Excel 2007 and later versions. The '.pot' is associated with PowerPoint Open XML Template, '.pptx' with PowerPoint Presentation, and '.2015' and '.don't' are not recognized file extensions for any Microsoft Office application. Therefore, none of the options provided, except '.xls' or '.xlsx', are correct. However, since '.xls' or '.xlsx' are not in the options, the question seems to have a mistake.