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'.

Ex 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

Ex Output:
3


Ex Input:
Question: Creatine phosphate: 
 Options:  <1> It is a low-energy hydrolysis compound. <2> It is a compound of energy storage in the kidney. <3> It is formed from ornithine. <4> It is a compound of energy storage in the muscle. <5> It is formed from tyrosine.

Ex Output:
4


Ex Input:
Question: What is the characteristic of the quasi-experimental research strategy that differentiates it from the experimental strategy ?: 
 Options:  <1> Single or very small cases are studied. <2> The study is carried out in simulated contexts. <3> There is no random assignment of participants to the different study conditions. <4> Several dependent variables are used. <5> It is done with samples of participants obtained by probabilistic sampling.

Ex Output:

3