उत्तर : 3. ". Pptx"
व्याख्या :

1. The file extension in PowerPoint 2010 is .pptx.

2. It is an open XML (Open XML) format used in PowerPoint 2007 and later versions.

3. .pptx files can also be opened with other presentation software, such as OpenOffice Impress, Google Slides, and Apple Keynote.