<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 72-year-old man presents to the physician with blood in his sputum for 3 days. He also mentions that he has had a cough for the last 3 months but thought that it was because of the winter season. He also has often experienced fatigue recently. His temperature is 37.0C 98.6F, the respiratory rate is 15min, the pulse is 67min, and the blood pressure is 12298 mm Hg. Auscultation of his chest reveals normal heart sounds but localized rhonchi over the right infrascapular region. A detailed diagnostic evaluation including a complete blood count and other serum biochemistry, chest radiogram, computed tomography of chest and abdomen, magnetic resonance imaging of the brain, bone scan, and pulmonary function tests are ordered, which confirm a diagnosis of limited-disease small cell lung cancer of 2.5 cm 1 in in diameter, located in the lower lobe of the right lung, with the involvement of ipsilateral hilar lymph nodes and intrapulmonary lymph nodes. The mediastinal, subcarinal, scalene or supraclavicular lymph nodes are not involved, and there is no distant metastasis. There is no additional comorbidity and his performance status is good. The patient does not have any contraindication to any chemotherapeutic agents or radiotherapy. Which of the following is the best treatment option for this patient?? A: Lobectomy with adjuvant topotecan-based chemotherapy, B: Pneumonectomy with adjuvant platinum-based chemotherapy and thoracic radiation therapy, C: Platinum-based chemotherapy plus etoposide and thoracic radiation therapy, D: Topotecan-based chemotherapy plus thoracic radiation therapy, E: Thoracic radiation therapy followed by prophylactic cranial irradiation,  <response>: This is a question about the best treatment option for a 72-year-old man diagnosed with limited-stage small cell lung cancer. Based on the details provided, it seems the cancer is localized to the lower right lung lobe and nearby lymph nodes, without distant metastases. The choices provided are different combinations of surgery lobectomy or pneumonectomy, chemotherapy platinum-based or topotecan-based, and radiation therapy thoracic or prophylactic cranial.For limited stage small cell lung cancer, the standard of care is concurrent chemoradiation therapy. Surgery is not typically recommended as these tumors are very responsive to chemotherapy and radiation. Prophylactic cranial irradiation may be considered after chemoradiation if there is a good response. C: Platinum-based chemotherapy plus etoposide and thoracic radiation therapy 