The following are multiple choice questions (with answers) about medical knowledge.   **Question:** Extra-radicular source of persistent endodontic infection is?   (A) Propionobacterium   (B) E.fecalis   (C) V.parvula)   (D) T.denticola
['(A) Propionobacterium <> answer', 'The following are multiple choice questions (with answers) about medical knowledge. <> instruction', '(A) Propionobacterium \n (B) E.fecalis \n (C) V.parvula) \n (D) T.denticola <> possible answers', '  Extra-radicular source of persistent endodontic infection is? <> context@']