Teacher:In this task, you are given a question and answer options for that question. Using this information, you have to classify each text into different topics: medicine, nursery, psychology, chemistry, pharmacology, biology.
Teacher: Now, understand the problem? Solve this instance: Question: What element plays a physiological role in the prevention of gastroesophageal reflux?
Options: <0> Upper esophageal sphincter <1> Angle of His. <2> Hernia of Hiato. <3> Purkinje angle. <4> Pyloric sphincter
Student:
pharmacology