Match the scientist in Column I with their contribution in Column II and choose the correct option.
| Column I | Scientist | Column II | Contribution |
|---|---|---|---|
| i | Alexander Van Humboldt | a | Estimated \(7\) million species around the globe |
| ii | Robert May | b | Rivet Popper Hypothesis |
| iii | David Tilman | c | Species-Area Relationship |
| iv | Paul Ehrlich | d | Productivity Stability Hypothesis |