Definition: In this task, you are given a multiple-choice question about healthcare. Answer the question based on your information and classify your answers into '1', '2', '3', and '4'.
Input: Question: Which of the following antidiabetics acts by inhibiting DPP-4 and prolonging the duration of the endogenous incretins GLP-1 and GIP ?:
Options: <1> Glimepiride <2> Repaglinide. <3> Sitagliptin <4> Rosiglitazone. <5> Tolbutamide
Output:
3