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: Pharmacology
[{'content': 'Which insulin is never mixed with other insulins? \nSelect and explain. \nA. Utile, B. Aspa, C. Lispro, D. Glargine', 'role': 'user'}, {'content': "Answer: D \nExplanation: Ans. is 'd' i.e., Glargine o All insulin preparations are supplied at neutral pH (7.2-7.4) except glargine (supplied at pH 4.0); therefore, glargine cannot be mixed with any insulin.", 'role': 'assistant'}]