<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 69-year-old man is brought to the emergency department because of a 1-week history of recurring black stools. On questioning, he reports fatigue and loss of appetite over the last 3 months. Twenty years ago, he underwent a partial gastrectomy for peptic ulcer disease. The patients father died of metastatic colon cancer at the age of 57 years. He is 163 cm 5 ft 4 in tall and weighs 55 kg 121 lb; BMI is 20.8 kgm2. He appears chronically ill. His temperature is 36.5C 97.7F, pulse is 105min, and blood pressure is 11570 mm Hg. The conjunctiva appear pale. Cardiopulmonary examination shows no abnormalities. The abdomen is soft and nontender. There is a well-healed scar on the upper abdomen. His hemoglobin concentration is 10.5 gdL and his mean corpuscular volume is 101 μm3. An upper endoscopy shows a large nodular mass on the anterior wall of the lesser curvature of the gastric stump. Biopsy samples are obtained, showing polypoid, glandular formation of irregular-shaped and fused gastric cells with intraluminal mucus, demonstrating an infiltrative growth. Which of the following is the most appropriate next step in the management of this patient?? A: Stool antigen test for H. pylori, B: Laparoscopy, C: Treatment with PPI, clarithromycin, and amoxicillin, D: Abdominopelvic CT scan, E: Vitamin B12 assessment,  <response>: This is a clinical vignette describing a 69-year-old man with a history of partial gastrectomy 20 years ago who now presents with 1 week of recurring black stools, fatigue, loss of appetite over 3 months, and a family history of colon cancer in his father. His physical exam is significant for pale conjunctivae and a well-healed upper abdominal scar. His labs show a microcytic anemia with hemoglobin of 10.5 gdL. Endoscopy reveals a large nodular mass in his gastric stump, and biopsy shows features consistent with adenocarcinoma. The key findings here are the patients recurring black stools, which indicate gastrointestinal bleeding, along with the endoscopic finding of a gastric mass concerning for malignancy. The most appropriate next step would be to further evaluate the extent of disease and staging with imaging. Stool antigen testing for H. pylori, PPIantibiotic treatment, and checking vitamin B12 levels do not evaluate the extent of his presumed gastric cancer. Laparoscopy could be used for staging but CT scan is less invasive and would be more appropriate as the next step.D: Abdominopelvic CT scan 