This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Stomach, Subject name: Pathology
[{'content': 'In early gastric carcinoma malignancy is confined to: \nSelect and explain. \nA. Mucosa, B. Mucosa and submucosa, C. Gastric wall without lymph node metastasis, D. Gastric glands', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Early gastric cancer: Tumor confined to mucosa and submucosa Late gastric cancer: Tumor penetrating into muscle layer and may even extend into serosa', 'role': 'assistant'}]