This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Pathology
[{'content': 'most common sign in any mitochondrial inheritence diseases? \nSelect and explain. \nA. ataxia, B. external ophthalmoplegia, C. psychosis, D. neurogenic weakness', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Mitochondrial diseases * significant clinical and genetic heterogeneity * syndromic and non-syndromic * often multi-system diseases * onset between bih and senescence * a common cause a chronic morbidity and more prevalent than previously thought Common phenotypes in adults PEO-Progressive External Ophthalmoplegia (m/c) K55- Kearns Sayre Syndrome MERRF= Myoclonic Epilepsy with Ragged Red Fibers MELAS= (Mitochondrial Encephalomyopathy, Lactic Acidosis and Stroke-like episodes) ref : robbins 10th ed', 'role': 'assistant'}]