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
In cardiac shock - 
Select and explain. 
A. SBP < 90 mm of Hg, B. DBP < 80 mm of Hg, C. Cardiac index <3.5, D. Stroke volume 70 ml
A: SBP < 90 mm of Hg
Answer: A: SBP < 90 mm of Hg 
Explanation: None