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: The interaction between the urea cycle and the citric acid cycle is carried out at the level of: 
 Options:  <1> Uric acid. <2> Succinate <3> Ammonia. <4> Urea. <5> Fumarate
Student:
5