Instructions: 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.
Input: Question: Reactivity is considered a source of error when using Observation as a method of obtaining information. Where does it come from?
Options: <0> From the context in which the Observation is generated. <1> Of the observed subject. <2> Of the chosen procedure. <3> From the observer. <4> Of the type of instrument chosen.
Output:
psychology