Task: Question Answering
Input (English): Question: A compound that has a five-membered aromatic heterocyclic skeleton with three carbon atoms and two nitrogens, the latter being positions 1 and 3, is called: 
 Options:  <1> Pirrol. <2> Pyrimidine <3> Pyrazole <4> Pyrazolidine. <5> Imidazole
Output (English): 5