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: Unknown
Thyroid hormone receptor which is predominantly expressed in CNS/Brain - 
Select and explain. 
A. a - 1, B. a - 2, C. b - 1, D. b - 2
C: b - 1
Answer: C: b - 1 
Explanation: Ans- b - 1 Ref-