Students are increasingly turning to online courses because they have become a better way to learn. Online courses offer students greater control over their own learning by enabling them to work at their own pace.Some other benefits are the engaging multimedia content, greater access to the instructor and the stimulating online interactions with other students and the teachers. All these can add to enhanced learning and improved retention.Another key feature is that online courses tend to include more frequent assessments. The more often students are assessed, the better their instructors can track progress and intervene when needed.I experienced all this myself when I completed a six-week online program through Columbia Business School. As a busy executive, the only way I was able to take such a course was online. And it proved to be an incredibly valuable and timely experience - highly relevant to my new job. I was able to do many of the lecture portions from my iPhone while sitting on a plane. I did coursework during the week and turned in weekly assignments on Sunday evening. And each Wednesday, I attended live online sessions with professors and students from around the world.Many students who have taken both face-to-face and online courses now rank their online experiences equal to or better than their more traditional classroom courses. We have reached a watershed moment when the discussion will no longer be about the relative merits of online learning, but how best to implement online programmes for maximum effect on student enrollment and success. Select the option that does NOT correctly complete the given sentence.Online course professors ______.

1. A
   check progress regularly
2. B
   do not permit peer interaction
3. C
   interact with student groups
4. D
   intervene when necessary