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: Surgery
True about carotid body tumor-a) Arises from pharyngeal wallb) Arises from baroreceptor cells.c) Commonly seen in high altitude habitantsd) 10% have family historye) FNAC is diagnostic 
Select and explain. 
A. ab, B. cd, C. bd, D. ac
B: cd
Answer: B: cd 
Explanation: Carotid body tumors arise from chemoreceptor cells of the carotid body (Baroreceptor cells are found in carotid sinus)
Since the chemoreceptor cells are stimulated by decreased arterial oxygen tension, a higher incidence of carotid body tumors is noted in oxygen deprived individuals i.e. cyanotic heart ds, chronic hypoxia in high altitude inhabitants.
According to Bailey 25/e p732- Family history is seen in -10% patients. (According to Schwartz its 35%)
FNAC & biopsy are contraindicated because of the highly vascular nature of the tumor.