<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 32-year-old woman patient presents to her family physician with recurrent retrosternal chest pain. She has had similar episodes for the past 7 months along with difficulty swallowing solid as well as liquid food. She recently completed an 8-week course of a proton pump inhibitor, but she is still bothered by the feeling that food gets stuck down her food pipe. Her pain is not related to exertion. She denies any history of acid reflux disease. Her blood pressure is 12581 mm Hg, respirations are 21min, pulse is 78min, and temperature is 36.7C 98.1F. She currently does not have pain. A barium swallow X-ray image is normal. Which of the following test would aid in the diagnosis of this patients condition?? A: Electrocardiogram, B: Upper GI endoscopy, C: Manometry, D: Additional therapy with proton pump inhibitors, E: Injection of botulinum toxin,  <response>: This is a patient with recurrent retrosternal chest pain and dysphagia. The pain is not related to exertion and she does not have a history of acid reflux disease, so cardiac and GERD causes are less likely. A barium swallow was normal. Her symptoms suggest an esophageal motility disorder like achalasia or diffuse esophageal spasm. Manometry would be helpful to evaluate esophageal motility and aid in the diagnosis. Upper endoscopy could reveal structural abnormalities but would not provide information about motility. ECG, PPI therapy, and botulinum toxin injection would not aid in the diagnosis.C: Manometry 