Task: Text Categorization
Input (English): Question: What is a prodrug? 
 Options:  <0> A drug of series of a therapeutic class. <1> A drug that has been withdrawn from the market. <2> An inactive product that is enzymatically converted to an active drug. <3> A compound of natural origin from which one or more drugs are obtained by hemisynthesis. <4> A drug that lacks activity but enhances the action of others.
Output (English): medicine