Task: Question Answering
Input (English): Question: Affinity chromatography is characterized because: 
 Options:  <1> It is a modality of gas chromatography. <2> It is similar to paper chromatography. <3> It is a separation process based on the very selective or specific interactions that exist between biological macromolecules. <4> It is a technique of separating compounds according to their molecular weight. <5> It is a variant of chromatography that employ relatively non-polar stationary phases and more polar solvents, in contrast to normal phase chromatography.
Output (English): 3