A 58-year-old man from rural India presents with progressive dysphagia and epigastric pain for 4 months. Upper endoscopy reveals a large ulcerated mass in the gastric antrum. Biopsy confirms adenocarcinoma. CT staging shows locally advanced disease (T3N2M0). He is deemed fit for neoadjuvant chemotherapy followed by surgery. What is the drug of choice for neoadjuvant treatment of locally advanced gastric cancer?