This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: New born infants, Subject name: Pediatrics
Cyanosis in newborn that disappears on crying is seen in? 
Select and explain. 
A. Laryngocoele, B. Unilateral choanal atresia, C. Bilateral choanal atresia, D. Foreign body
C: Bilateral choanal atresia
Answer: C: Bilateral choanal atresia 
Explanation: *Bilateral choanal atresia is due to persistence of bucconasal membrane. Newborn, being a natural nose breather, presents with respiratory obstruction leading to cyanosis. However, if the infant cries and takes a breath through the mouth, the airway obstruction is momentarily relieved and thus cyanosis disappears. Reference : page 163 Diseases of Ear, Nose and Throat & Head and neck surgery P L Dhingra 7 th h edition