Seven friends, Alok, Dheeraj, Harsh, Karan, Naman, Ravi, and Vasu, are sitting in a straight line facing north. Ravi sits second to the left of Harsh. Vasu sits second to the left of Karan. Karan sits to the immediate left of Ravi. Naman sits third to the right of Dheeraj. Vasu does not sit on any of the extreme ends. Three of the following four are alike in a certain way based on the given arrangement and thus form a group. Which is the one that does not belong to that group?