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: Dental
Underlying pathology of Nevus anemicus is: 
Select and explain. 
A. Autoimmune destruction of melanocytes, B. Arrest of migration of melanocytes, C. Abnormal vasoconstriction, D. Defect in tyrosinase enzyme
C: Abnormal vasoconstriction
Answer: C: Abnormal vasoconstriction 
Explanation: Nevus anemicus presents as a localized area of skin blanching and hypopigmentation because of abnormal vasoconstriction due to increased sensitivity of blood vessels to catecholamines.