Double Bubble sign is seen with:

Ans is 'b' i.e. Duodenal atresia "The ultrasound hallmark of duodenal atresia is the 'double bubble sign'. This consists of two adjacent, fluid-filled cavities in the upper abdomen: a lateral and usually somewhat larger cavity representing the dilated stomach, and a medial cavity representing the distended proximal duodenum between the pylorus and the stenosis."- Ultrasound in obstetrics and gynecology By Eberhard Merz, F. Bahlmann 2/e p298Double bubble sign:The double bubble sign is a finding observed on radiographs of newborns and infants. It is reproducible with a variety of other imaging modalities, including upper gastrointestinal studies and prenatal sonography. The finding depicts two air-filled structures in the upper abdomen, with little or no air distally. Horizontal-beam radiographs will demonstrate air and fluid levels in both bubbles.The first bubble (proximal and left sided) is - stomachThe second bubble (to the right of the midline) is - duodenumThe detection of the double bubble sign leads to suspicion of a number of structural anomalies, all of which cause duodenal obstruction.Causes:Intrinsic causes areExtrinsic causes are- duodenal atresia,- annular pancreas,- duodenal stenosis,- malrotation of the gut with obstruction produced byandmidgut volvulus or by Ladd bands, and- duodenal webs;- preduodenal position of the portal vein.The specific duodenal structural anomaly causing the obstruction determines the appearance, prominence, and presence of air distal to the obstruction. Duodenal atresia produces complete obstruction, partially obstructing anomalies, such as duodenal web or duodenal stenosis, allow passage of some air distal to the obstruction and a less dramatic double bubble.