This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Orthopaedics
A patient with leprosy presents with clumsiness of hand. His ulnar nerve is affected. Clumsiness is due to palsy of which muscle - 
Select and explain. 
A. Extensor carpi ulnaris, B. Abductor pollicis brevis, C. Oppenens pollicis, D. Interosseous muscle
D: Interosseous muscle
Answer: D: Interosseous muscle 
Explanation: Clumsiness is due to paralysis of muscles which are involved in fine movement i.e., interossei, lumbricals and hypothenar muscles.