This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Neuroradiology, Subject name: Radiology
[{'content': 'Racing car sign is seen in \nSelect and explain. \nA. Lipoma of corpus callosum, B. Agenesis of corpus callosum, C. Necrosis of corpus callosum, D. Degeneration of corpus callosum', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Racing car sign/Moose head sign/Viking Helmet Sign is seen in Agenesis of Corpus Callosum on MRI. Probst bundles denote white matter fibers normally destined to cross the corpus callosum that instead parallel the interhemispheric fissure in patients with agenesis of corpus callosum. These lead to widely spaced lateral ventricles forming the characteristic racing car sign. High riding 3rd ventricle is also seen in CC agenesis.', 'role': 'assistant'}]