The following are multiple choice questions (with answers) about medical knowledge.   **Question:** Syncope is usually caused by:   (A) Vasoconstriction   (B) Cerebral ischemia   (C) Cerebral hyperemia   (D) Decrease in the vascular bed
['(B) Cerebral ischemia <> answer', 'The following are multiple choice questions (with answers) about medical knowledge. <> instruction', '(A) Vasoconstriction \n (B) Cerebral ischemia \n (C) Cerebral hyperemia \n (D) Decrease in the vascular bed <> possible answers', '  Syncope is usually caused by: <> context@']