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: Physiology
Cyclic GMP act on : 
Select and explain. 
A. Insulin, B. Thyroxin, C. Atrial natriuretic peptide, D. Growth harmone
C: Atrial natriuretic peptide
Answer: C: Atrial natriuretic peptide 
Explanation: C i.e. Atrial natriuretic peptide