Task: Question Answering
Input (English): Question: In the alcaptonuria the defective enzyme can be: 
 Options:  <1> Dihydrobiopterin reductase. <2> Tyrosine aminotransferase. <3> p-hydroxyphenylpyruvate dioxygenase. <4> Homogentisic 1,2-dioxygenase. <5> Fumarilacetoacetasa.
Output (English): 4