What is the default file extension of MS Word 2016?

File extensions are crucial identifiers that indicate the type of a file and the software program associated with it. The question asks for the default file extension of MS Word 2016. The correct answer is .docx. This extension was introduced with Microsoft Word 2007 and has been the standard for all subsequent versions, including Word 2016. The 'x' signifies that it is based on Office Open XML (OOXML), an XML-based format that offers benefits like smaller file sizes, improved data recovery, and enhanced security compared to older formats. The .doc extension was the default for older versions of Word (Word 97-2003). .dot is the extension for Word document templates, used to create new documents with predefined settings. .word is not a recognized or standard file extension for Microsoft Word documents. Therefore, .docx is the correct default extension.