In this task, you are given a multiple-choice question about healthcare. Answer the question based on your information and classify your answers into '1', '2', '3', and '4'.

Q: Question: Regarding gastroesophageal reflux disease, which of the following statements is true? 
 Options:  <1> The intensity and frequency of heartburn has little relationship with the presence and severity of endoscopic esophagitis. <2> Most patients with gastroesophageal reflux disease have esophagitis at endoscopy. <3> Treatment with proton pump inhibitors usually achieves good control of symptoms but is not superior to placebo in the endoscopic cure of esophagitis. <4> Barrett's esophagus can progress to low-grade epithelial dysplasia, high-grade epithelial dysplasia, and finally squamous cell carcinoma of the esophagus. <5> Endoscopic screening and surveillance programs have unequivocally shown to be able to reduce mortality in patients with Barrett's esophagus.

A: 1
****
Q: Question: ADH increases the osmolality of the renal interstitial medium because it increases: 
 Options:  <1> The permeability to urea in the collector tube. <2> The water permeability of the ascending loop of Henle. <3> The flow in the straight vessels. <4> The reabsorption of NaCl in the collecting tubule. <5> The renal excretion of water.

A: 1
****
Q: Question: What does the amperometric detector measure in high performance liquid chromatography (HPLC)? 
 Options:  <1> Potential difference. <2> Electric conductivity. <3> Thermal conductivity. <4> Electric resistance. <5> Intensity of electric current.

A:
5
****