This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology, Subject name: Pharmacology
Insulin acts through which receptor? (REPEAT) 
Select and explain. 
A. GPCR, B. Enzyme-linked, C. Intracellular, D. Ion channel
B: Enzyme-linked
Answer: B: Enzyme-linked 
Explanation: Insulin acts through tyrosine phosphate kinase-enzyme.