This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Drugs, Subject name: Medicine
Which of the following is selective myosin activator? 
Select and explain. 
A. Istaroxime, B. Omecamtiv & Mecarbil, C. Tolvaptan, D. Levosimendan
B: Omecamtiv & Mecarbil
Answer: B: Omecamtiv & Mecarbil 
Explanation: Ans. B. Omecamtiv & MecarbilThese are selective Myosin activator. They prolong the ejection period and increases fractional shortening.