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 Q]: Question: Epidemiology allows early detection of changes in the incidence of a certain disease in the population. For this, the most correct thing is to use: 
 Options:  <1> The etiological investigation. <2> The description of the natural history of the disease. <3> Epidemiological surveillance. <4> The evaluation of the functioning of the services. <5> None of the previous answers is correct.
[EX A]: 3

[EX Q]: Question: In economic evaluations, which of the following costs correspond to indirect non-health costs? 
 Options:  <1> Hospitalization of the patient. <2> Care at the patient's home. <3> Loss of patient productivity. <4> Travel expenses of the patient. <5> Rehabilitation of the patient.
[EX A]: 3

[EX Q]: Question: Indicate which of the following compounds has antioxidant action: 
 Options:  <1> Vitamin B. <2> Vitamin D. <3> Vitamin E. <4> All the previous ones <5> None of the above.
[EX A]:
3