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
Cardiac contractility is inhibited by -a) Digitalis useb) Respiratory acidosisc) Metabolic alkalosisd) ↓PO4e) Hypothermia 
Select and explain. 
A. abc, B. ade, C. ace, D. bde
D: bde
Answer: D: bde 
Explanation: None