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.

Q: Question: What is the procedure called instrumental conditioning in which the instrumental response eliminates or prevents the occurrence of an aversive stimulus ?: 
 Options:  <0> Positive reinforcement. <1> Punishment. <2> Negative reinforcement. <3> Omission. <4> Extinction.

A: psychology
****
Q: Question: Which of the following is currently the only contraindication for conservative surgical treatment in breast cancer? 
 Options:  <0> Prior radiotherapy. <1> Tumor of 4 cm. <2> Axillary metastasis. <3> Multifocal tumor <4> Pregnancy of 32 weeks.

A: medicine
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Q: Question: Which of the following compounds in a fundamental intermediate of the synthesis of triacylglycerols and phospholipids: 
 Options:  <0> CDP-choline. <1> Phosphatidate <2> Triglyceride <3> Phosphatidylserine <4> CDP-diacylglycerol.

A:
chemistry
****