Step 1: Understanding the Terms.
- Neutralism: Neither species is affected by the other.
- Allelopathy: Direct inhibition of one species by the other using toxic compounds.
- Amensalism: One species is inhibited while the other is unaffected.
- Mutualism: Both species benefit from the interaction.
Step 2: Analyzing the Options.
- (A) P-I, Q-II, R-III, S-IV: This is incorrect because the pairings do not match the correct definitions of interactions.
- (B) P-III, Q-II, R-IV, S-I: This is incorrect. The pairing for Neutralism (P) is wrong here.
- (C) P-IV, Q-III, R-II, S-I: This is correct. P corresponds to Neutralism (I), Q corresponds to Allelopathy (II), R corresponds to Amensalism (III), and S corresponds to Mutualism (I).
- (D) P-III, Q-IV, R-II, S-I: This is incorrect. The pairings are mismatched.
Step 3: Conclusion.
The correct answer is (C) P-IV, Q-III, R-II, S-I, as the interaction types are matched correctly with their respective descriptions.