Step 1: Understand the excretory organs
Different animal groups have distinct excretory structures based on their evolutionary adaptations and physiological needs.
Step 2: Match each animal group with its excretory organ
1. A. Mollusca (Mollusks)
Mollusks use nephridia for excretion.
Correct match: II. Nephridia
2. B. Arthropoda (Arthropods)
Arthropods use Malpighian tubules for excretion.
Correct match: IV. Malpighian tubules
3. C. Annelida (Segmented Worms)
Segmented worms use nephridia for excretion.
Correct match: II. Nephridia
4. D. Platyhelminthes (Flatworms)
Flatworms use flame cells for excretion.
Correct match: I. Flame Cell
Step 3: Conclusion
The correct matches are:
$$
{\text{A-II, B-IV, C-II, D-I}}
$$