The following are multiple choice questions (with answers) about medical knowledge.   **Question:** Which of the following vessels supply the anal canal?   (A) Superior rectal aery   (B) Middle rectal aery   (C) Inferior rectal aery   (D) all of the following
['(D) all of the following <> answer', 'The following are multiple choice questions (with answers) about medical knowledge. <> instruction', '(A) Superior rectal aery \n (B) Middle rectal aery \n (C) Inferior rectal aery \n (D) all of the following <> possible answers', '  Which of the following vessels supply the anal canal? <> context@']