<prompt> A coin foreign body is stuck in esophagus at 25cm from incisors. This is approximately situated at which of the following levels?Left mainstem bronchusDiaphragmCricopharyngeal constrictionGastroesophageal junction  <response>: On endoscopy, 3 narrowings are seen from upper incisors. Mnemonic B - 15 AL - 25 D - 40 B - At beginningcricopharynx 15 cm from upper incisors A- At Arch of aoa 25cm from upper incisors L- At Left Bronchus 25 cm from upper incisors D- At Diaphragm 40cm from upper incisiors 