Which application allows users to access Microsoft Office documents online?

The application that allows users to access Microsoft Office documents online is not Offline Office. Instead, the correct option is typically a web-based version of Microsoft Office, such as Office Online (now known as Microsoft 365).

Offline Office refers to the installed version of Microsoft Office applications like Word, Excel, and PowerPoint, which do not enable users to access documents online or collaborate in real-time over the internet. While users can upload documents created with Offline Office to cloud storage services like OneDrive or SharePoint for online access, Offline Office itself does not facilitate direct online interaction with documents.

In contrast, Adobe Reader is primarily used for PDF files, QuickTime is a multimedia framework for video and audio playback, and ActiveX is a software framework used for interactive content in web pages but does not pertain to document editing or management.

Thus, to access Microsoft Office documents online, a dedicated online service or application designed for that purpose is required, which is why Offline Office is not the correct answer.