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.

Q: 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

A: pharmacology
****
Q: Question: The minimum amount of auditory stimulation needed to begin to identify the lyrics of a song is a threshold: 
 Options:  <0> Absolute. <1> Subliminal. <2> Differential. <3> Relative. <4> Musical.

A: psychology
****
Q: Question: D-glyceraldehyde and dihydroxyacetone: 
 Options:  <0> They present an asymmetric carbon. <1> They are aldosas. <2> They are enantiomers. <3> They present optical activity. <4> They have the same formula.

A:
biology
****