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: Pharmacology
Which drug directly stimulates contraction of cardiac muscle 
Select and explain. 
A. Digitalis, B. ACE inhibitors, C. Nesiritide, D. Losaan
A: Digitalis
Answer: A: Digitalis 
Explanation: Ans. is'a'i.e., DigitalisCardiac glycosides (digitalis) act directly on the hea to increase the force of contraction.