Task: Question Answering
Input (English): Question: Which of the following structural families of drugs act as neuroleptic agents? 
 Options:  <1> Benzothiazepines (diltiazem). <2> Butyrophenones (haloperidol). <3> Phenylpiperidines (pethidine). <4> Aryloxypropanolamines (atenolol). <5> 1,4-dihydropyridines (nifedipine).
Output (English): 2