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: Medicine
All of true about HOCM except 
Select and explain. 
A. Asymmetrical septal thickness, B. Left ventricular outflow obstruction, C. Double apical impule, D. Digitalis is useful
D: Digitalis is useful
Answer: D: Digitalis is useful 
Explanation: None