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: Anatomy
Among the following muscles, the one that is found in the first layer of the sole is: 
Select and explain. 
A. Adductor hallucis, B. Flexor digitorum brevis, C. Flexor digiti minimi brevis, D. Flexor hallucis longus
B: Flexor digitorum brevis
Answer: B: Flexor digitorum brevis 
Explanation: Flexor digitorum brevis