Answer:
XLSX
Step-by-step explanation:
The XLSX file extension is associated with files saved with Microsoft Excel (2007/2010), one of the most popular and powerful tools you can use to create and format spreadsheets, graphs and much more. The . xlsx files are used in Microsoft Excel (2007/2010) for Workbooks, spreadsheet, and document files.
Excel file formats:
Format Extension
Excel Workbook - .xlsx
Excel Macro-Enabled Workbook (code)- .xlsm
Excel Binary Workbook- .xlsb
Template- .xltx