This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.V.S, Subject name: Pediatrics
True about TOF 
Select and explain. 
A. Recurrent chest infection, B. Clubbing of feet, C. Squatting, D. Cyanotic spells
B: Clubbing of feet
Answer: B: Clubbing of feet 
Explanation: Tetralogy of Fallot symptoms vary, depending on the extent of obstruction of blood flow out of the right ventricle and into the lungs. Signs and symptoms may include: A bluish coloration of the skin caused by blood low in oxygen (cyanosis) Shoness of breath and rapid breathing, especially during feeding or exercise Loss of consciousness (fainting) Clubbing of fingers and toes -- an abnormal, rounded shape of the nail bed Poor weight gain Tiring easily during play or exercise Irritability Prolonged crying A hea murmur Ref : Davidson principal and practice of medicine, 22nd edition, p.no:634