Ans. is 'd' i.e., Expiratory stridor Larvngomalaciao It is the most common congenital abnormality of the larynx. Larvngomalacia is the most frequent cause of stridor or noisy breathing in infants. It occurs as a result of a floppy portion of the larynx (in supraglottic larynx) that has not yet developed the strength to provide rigid support to the airway. During inspiration negative pressure is created through larynx, which results in a collapse of these structures into the airway and a narrower breathing passage. Partial obstruction is the source of the noise with breathing (stridor), and sometimes cyanosis,o The hallmark sign includes intermittent stridor mostly in inspiration. It is usually more prominent when the infant is lying on his/her back (supine position, crying, feeding, excited or has a cold. Stridor gets relieved on placing the patient in prone position. This is usually first noticed in the first few weeks of life.o It may worsen over the first few months and become louder. This is because as the baby grows, inspiratory force is greater, which causes greater collapse of the laryngeal structures into the airway. This is usually worst at 3-6 months and then gradually improves as the rigidity of the cartilage improves,o Most children are symptom free by 1 to 2 years.o Sometimes, cyanosis may occur,o Direct laryngoscopy shows :-Omega shaped epiglottis, i.e. elongated and curled on itself.Floopy, tall, foreshortened and thin aryepiglottic folds.Prominent arytenoids.o In most patients laryngomalacia is a self limiting condition. Treatment of larvngomalacia is reassurance to the parents and early antibiotic therapy for upper respiratory tract infections.