Task: Question Answering
Input (English): 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.
Output (English): 3