IIT Bombay X is a non-profit MOOC platform developed by IIT Bombay using the open-source platform_________

The correct option is Open edX.

IIT BombayX is an online learning platform that offers Massive Open Online Courses (MOOCs). It was designed and developed by the Indian Institute of Technology Bombay (IIT Bombay) to provide high-quality education to learners globally.

To power this platform, IIT Bombay utilized Open edX, a highly scalable, open-source course management system originally developed by edX (founded by MIT and Harvard). Open edX provides the underlying technology, hosting engine, and learning management tools that allow universities and institutions to create, deliver, and manage online courses at scale.

While other options like Joomla and Drupal are general-purpose Content Management Systems (CMS), and Sakai is a traditional learning management system, Open edX was specifically chosen for its advanced MOOC infrastructure and active global open-source community support.