Six students Mani, Nisha, Ojas, Parth, Qasim, and Riya

Solution

 Since only two students are sitting to the right of Qasim, he must be at the 3rd place from the right end.  Riya is sitting to the immediate left of Parth and Mani is sitting between Parth and Qasim. This means Riya is at the extreme left end and Parth is at the 2nd place from the left.  Nisha and Ojas could occupy either of the extreme right position or 2nd place from the right. Final arrangement is as shown below. From the above it is clear that Riya is sitting at the extreme left end. Hence the correct answer is (B).