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.

Example Input: Question: Immunoglobulin isotype change affects:
Options: <0> The constant regions of the heavy chains. <1> The constant regions of the light chains. <2> The totality of heavy chains. <3> The entire immunoglobulin molecule. <4> The hypervariable regions of the heavy chains.
Example Output: biology

Example Input: Question: One of the following types of transport through membranes does NOT exist:
Options: <0> Ion transport facilitated by ionophore (against electrochemical gradient). <1> Facilitated diffusion (in favor of electrochemical gradient) <2> Primary active transport (against electrochemical gradient). <3> Ionic channel (in favor of electrochemical gradient). <4> Simple diffusion (in favor of concentration gradient).
Example Output: pharmacology

Example Input: Question: The classical pathway of complement is activated in response to:
Options: <0> Antigen-antibody complexes. <1> Direct binding of C3b to bacterial walls. <2> Microbial glycolipids. <3> Properdin <4> The C-reactive protein.
Example Output:
biology