Task: Text Categorization
Input (English): Question: The enantiomers of a molecule are: 
 Options:  <0> Very different in all its chemical and physical properties. <1> Superimposed mirror images. <2> Distinguishable by their optical activity. <3> The result of the cyclization of a molecule in different positions. <4> Interconvertible without rupture of covalent bonds.
Output (English): biology