This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Medicine
[{'content': "All are true of pancoast's tumor except -  a) Deltoid muscle atrophy  b) Treated with radiotherapy & chemotherapy  c) Horner's syndrome  d) Pain along the ulnar border of the forearm \nSelect and explain. \nA. ab, B. bc, C. abc, D. cd", 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]