This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Upper limb, Subject name: Anatomy
Which of the following movement of thumb is lost in ulnar nerve injury 
Select and explain. 
A. Opposition, B. Extension, C. Adduction, D. Abduction
C: Adduction
Answer: C: Adduction 
Explanation: Weakness of adduction of the thumb, which may be assessed by the presence of Froment&;s sign.