This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Polycythemia, Subject name: Medicine
Gaisbock syndrome is known as- 
Select and explain. 
A. Primary familial polycytemia, B. High altitude Erythrocytosis, C. Spurious Polycythemia, D. Polycythemia vera
C: Spurious Polycythemia
Answer: C: Spurious Polycythemia 
Explanation: Ans. is 'c' i.e., Spurious Polycythemia o Gaisbock syndrome refers to spurious polycythemia or relative erythrocytosis due to decreased plasma volume.