This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pathology
[{'content': 'Severe hypovolemic shock occurs when blood volume less is - \nSelect and explain. \nA. > 10 %, B. > 20 %, C. > 30 %, D. >40%', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Hypovolemic shock\n\nHypovolemic shock is the most common form of shock.\n\n\n\nThis is due to a decrease in blood volume either by the loss of blood or plasma.\nGrading of hypovolemic shock\n\n\nMild hypovolemia\xa0→\xa0When volume loss is less than 20%. There is generally mild tachycardia but relatively few external signs.\nModerate hypovolemia\xa0→ When volume loss is between 20-40%. Normal blood pressure is maintained\n\tin the supine position, but there are postural hypotension and tachycardia on erect posture.\nSevere hypovolemia\xa0→\xa0When volume loss is > 40%. The classical signs of shock appear i.e., marked tachycardia, hypotension, disorientation.', 'role': 'assistant'}]