Step 1: Understanding the phonetic classification. 
  
In linguistics, sounds are classified based on their place of articulation — the point in the mouth or throat where airflow restriction occurs. 
  
This question matches Khasi consonants with their phonetic categories. 
  
Step 2: Explanation of each sound group. 
  
- (A) Nia, khlia, ain – Palatal: These sounds are produced with the tongue touching the hard palate, hence classified as palatal. 
  
- (B) Pah, bam, mar – Bilabial: Both lips are used to produce these sounds, which is characteristic of bilabial consonants. 
  
- (C) Kah, skum, suk – Velar: These are articulated at the soft part of the palate near the back of the mouth, making them velar. 
  
- (D) Shah, kshald, shish – Alveo-palatal: The tongue touches the alveolar ridge and the palate simultaneously, forming alveo-palatal sounds. 
  
Step 3: Phonetic accuracy. 
  
Each match corresponds to how Khasi phonemes align with general phonetic principles in articulatory phonology. 
  
Understanding these helps in pronunciation, spelling, and phonetic transcription. 
  
Step 4: Conclusion. 
  
Thus, the correct answer is (A) - I, (B) - IV, (C) - II, (D) - III.