Q: In this task, you are given a question and answer options for that question. Using this information, you have to classify each text into different topics: medicine, nursery, psychology, chemistry, pharmacology, biology.
Question: Among the sources used to make the diagnosis of health of a community, it is essential to know: 
 Options:  <0> Census of the population. <1> Notifiable diseases registration. <2> Potable water supply. <3> Waiting lists. <4> All are correct.
A:
nursery