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'.

Example Input: Question: We want to study if Vitamin D can increase the incidence of breast cancer. In our area we have a population registry of cancer. To achieve our goal, all women diagnosed with breast cancer are selected from the register we have and each case pairs with two controls. What study design has been chosen? 
 Options:  <1> Prospective cohort study. <2> Cases and controls study. <3> Case-control study nested. <4> Retrospective cohort study. <5> Ecological study
Example Output: 3

Example Input: Question: Which of the following moments of the electrocardiogram corresponds to the depolarization stage of the ventricular myocardium ?: 
 Options:  <1> Onda P. <2> Onda T. <3> Segment T-P. <4> Segment P-Q. <5> QRS wave.
Example Output: 5

Example Input: Question: The generation of the cold vapor is a form of introduction of the sample for the atomization that is used in atomic absorption spectrometry (EAA) to analyze: 
 Options:  <1> Lead and Arsenic. <2> Mercury. <3> Elements that have a low vapor pressure at room temperature. <4> Halogens of high molecular weight. <5> Alcalinotérreos.
Example Output:
2