Randhir has more marks than Kunal + Debu. This means Randhir scored significantly higher than these two combined, but it doesn't give us a clear comparison with Neha, Sonal, or Shankar.

Kunal + Shankar have more marks than Randhir. Individually, Shankar might have more marks than Randhir, but this isn’t confirmed yet. However, this shows Shankar contributes significantly.

Sonal has more marks than Shankar. This means Sonal is ahead of Shankar and likely ahead of Kunal, Debu, and possibly Randhir.

Neha has more marks than Randhir. This means Neha is ahead of Randhir, who is already ahead of Kunal and Debu.

Comparison of the top scorers: Neha > Randhir Sonal > Shankar (and possibly Randhir, depending on Shankar's position). Kunal and Debu are lower in rank. Thus, Neha or Sonal could have the highest marks. However, the data doesn’t compare Neha directly with Sonal.

Answer: D. Data are inadequate