This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General physiology, Subject name: Physiology
Calmodulin acts by 
Select and explain. 
A. Opening of Na+ channels, B. Phosphorylation of myosine by protein kinase, C. Activation of Na+-K+ pump, D. Dephosphorylation by protein kinase
B: Phosphorylation of myosine by protein kinase
Answer: B: Phosphorylation of myosine by protein kinase 
Explanation: Calmodulin contains myosin light-chain kinase, which phosphorylates myosin and phosphorylase kinase which activates phosphorylase.(Ref: Textbook of physiology AK JAIN 5th edition page no.20)