Task: Text Categorization
Input (English): Question: The type of epidemiological study indicated to evaluate, in a population initially exempt from the health problem under study, the association between a risk factor and the onset of the disease is: 
 Options:  <0> Randomized clinical trial. <1> Quasi experimental. <2> Ecological studies <3> Cases and controls study. <4> Cohort study.
Output (English): nursery