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: Pathology
Following injury to a blood vessel, immediate haemostasis is achieved by 
Select and explain. 
A. Fibrin deposition, B. Vasoconstriction, C. Platelet adhesion, D. Thrombosis
B: Vasoconstriction
Answer: B: Vasoconstriction 
Explanation: None