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: In mass spectrometry, the most common fragmentation pattern is the break in α, which cleaves the alkyl bond adjacent to the carbonyl to give: 
 Options:  <0> The corresponding acyl cation and an alkyl radical. <1> The corresponding acyl anion and an alkyl radical. <2> The corresponding acyl radical and an alkyl radical. <3> The corresponding acyl cation and an alkyl cation. <4> The corresponding acyl anion and an alkyl anion.

A: chemistry
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Q: Question: Regarding benign prostatic hypertrophy, it is NOT true that: 
 Options:  <0> Abdominal ultrasound is a non-invasive method to assess prostate size and post-voiding residual. <1> It can cause increases in PSA levels. <2> Rectal examination is a method to estimate prostate size. <3> Treatment with 5-alpha reductase inhibitors decreases symptoms. <4> It is a precancerous lesion.

A: medicine
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Q: Question: Histidine is characterized by: 
 Options:  <0> Present an indole group in its structure. <1> Present a unique N in its structure. <2> A side chain of aromatic character. <3> A side chain that can take or release protons at physiological pH. <4> Being a protein involved in inflammation.

A:
biology
****