Teacher: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'.
Teacher: Now, understand the problem? Solve this instance: Question: Mesna (sodium 2-mercaptoethanesulfonate) is used together with cyclophosphamide in antitumor therapy because:
Options: <1> They form a ternary complex with DNA that prevents replication. <2> Mesna inactivates a toxic metabolite that results from the activation of cyclophosphamide. <3> Both are DNA alkylating agents. <4> The oxidizing properties of mesna increase the cytotoxicity of cyclophosphamide. <5> Mesna inhibits cytochrome P-450 that oxidizes and degrades cyclophosphamide.
Student:
2