This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology, Subject name: Pediatrics
Which of the following is a rapid acting insulin? 
Select and explain. 
A. Glargine, B. Detemir, C. Lente, D. Glulisine
D: Glulisine
Answer: D: Glulisine 
Explanation: d. Glulisine(Ref: Nelson's 20/e p 2760-2780, Ghai 8/e p 541-548)Ultrashort acting Insulins include: Insulin Lispro, Glulisine and Aspart.