This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Chronic Inflammation, Subject name: Pathology
Procalcitonin is used as marker of: 
Select and explain. 
A. Cardiac dysfunction in acute coronary syndrome, B. Menstrual periodicity, C. Pituitary function, D. Sepsis
D: Sepsis
Answer: D: Sepsis 
Explanation: Procalcitonin is an acute phase reactant which is now useful for being a marker of sepsis.