This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Upper limb : Miscellaneous, Subject name: Anatomy
A patient with Bennett fracture (a fracture of the base of the first metacarpal bone) experiences an impaired thumb movement. Which of the following intrinsic muscles of the thumb is most likely injured? 
Select and explain. 
A. Abductor pollicis brevis, B. Flexor pollicis brevis (superficial head), C. Opponens pollicis, D. Adductor pollicis
C: Opponens pollicis
Answer: C: Opponens pollicis 
Explanation: The opponens pollicis inses on the first metacarpal. All other intrinsic muscles of the thumb, including the abductor pollicis brevis, the flexor pollicis brevis, and the adductor pollicis muscles, inse on the proximal phalanges.