This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Circulation: Cardiac Output, Venous Return, Subject name: Physiology
[{'content': 'Changes in cardiac output is minimal during: \nSelect and explain. \nA. Sleep, B. From supine to standing position, C. Exercise, D. Arrhythmias', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ref: Pal GK. Cardiac output. In: Textbook of Medical Physiology. Ahuja Publishing House. 2007; 74: 607.Explanation:Increased cardiac outputExerciseAnxietyEmotion and excitementT environmental temperatureEatingPregnancyDecrease in cardiac outputStanding from supineSweatingNo change in cardiac outputSleepMild to moderate change in environmental temperature', 'role': 'assistant'}]