Ans. is 'c' i.e., Right dorsal aorta o Normally, Right dorsal aorta disappears during development.o Persistent of right dorsal aorta distal to the origin of right intersegmental artery results in formation of double aortic arch.o During 8th week of infra uterine life, the final fetal arterial arrangement is achieved.AORTIC ARCHFateIMaxillary arteryIIHyoid and stapedial arteriesIIICarotid arteriesIVLeft - Arch of aortaRight - Proximal part of right subclavianVDegeneratesVILeft - Proximal part forms left pulmonary artery and distal part persists as ductus arteriosusRight - Right pulmonary arteryVII intersegmentary arteryRight - Distal part of right subclavianLeft - Left subclaviano With a double aortic arch, the right dorsal aorta persists between the origin of the seventh intersegmentary artery and its junction with the left dorsal aorta. A vascular ring surrounds the trachea and esophagus and compresses these structures.Also knowBlood vesselDevelopment componentsAscending aortaTruncus arteriosusArch of aorta1. Ventral part of aortic sac2. Left horn of aortic sac3. Left 4th arch arteryDescending aorta1. Left dorsal aorta beyond 7th cervical intersegmental artery'2. Fused dorsal aortaeBrachiocephalic arteryRight horn of aortic sac in which right 3rd and 4th arch arteries are opening.Common carotid3rd arch artery proximal to external carotid bud,Internal carotid artery3rd arch artery distal to external carotid bud and dorsal aorta cranial to attachment of 3rd arch artery.External carotid arteryNew offshoot from 3rd arch.Subclavian artery Right1. Right 4th arch artery.2. Right 7th cervical intersegmental artery'.LeftLeft 7th cervical intersegmental artery.Pulmonary trunkTruncus arteriosusPulmonary' artery'6th arch artery' (proximal part)Ductus arteriosusDistal part of left 6th arch artery between pulmonary artery and descending aorta.