Task: Text Categorization
Input (English): Question: In ion exchange chromatography, the carboxylic acid functional group is used as: 
 Options:  <0> As a strong anion exchanger in ion exchange resins. <1> As a strong cation exchanger in ion exchange resins. <2> As a weak anion exchanger in ion exchange resins. <3> As a weak cation exchanger in ion exchange resins. <4> It is never used in ion exchange.
Output (English): pharmacology