Which of the following file types can NOT be saved using the Save to Google Drive extension?

The ability to save various file types using the Save to Google Drive extension primarily revolves around the nature of the extension and the compatibility of formats with Google Drive. Google Drive supports a range of file types, but certain file formats are typically directly associated with its native applications.

In this instance, a Word Document (often .doc or .docx) is not inherently designed to be saved or edited directly within Google Drive's web interface as a native Google format. While users can upload and store Word Documents in Google Drive, they generally do so by converting or uploading the file, rather than saving through the extension specifically meant for use within a Google application. The extension is mainly optimized for seamless integration with file types that align closely with Google’s own productivity tools.

Conversely, file types like PNG and HTML can be saved to Google Drive using the extension because they are compatible formats that can be easily handled and stored by the platform. Google Docs is obviously a native file type for Google Drive, allowing documents to be created and managed directly within its ecosystem. Thus, the distinction lies in the compatibility and intended usage of the file types relative to the Google Drive environment.