Instructions: 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: The clinical sensitivity of an analytical parameter (test) is defined as: 
 Options:  <1> The mean concentrations of this test in healthy patients. <2> A pathological concentration of the test in the presence of the disease. <3> A pathological concentration of the test in the absence of the disease. <4> A normal concentration of the test in the absence of the disease. <5> A normal concentration of the test in the presence of the disease.
Output:
2