In this task, you are given a multiple-choice question about healthcare. Answer the question based on your information and classify your answers into '1', '2', '3', and '4'.

Question: The determination of cyanide by the Liebig method is based on the addition of a silver nitrate standard solution: 
 Options:  <1> Until complete precipitation of silver cyanide. <2> Until the precipitation of silver cyanide begins. <3> Until the appearance of a red precipitate of silver chromate. <4> Until the AgCN complex is quantitatively formed. <5> Until the precipitation of silver iodide, yellow.
2

Question: Point out the correct answer regarding therapy for Rehm's depression: 
 Options:  <1> It focuses on three processes: self-tracking, self-esteem and self-reinforcement. <2> It has no empirical evidence to be considered well-established treatment. <3> Each of its components separately have been shown to be as effective as the complete treatment. <4> It presents a strong cognitive component. <5> It has been shown superior to interpersonal therapy and problem solving.
3

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.

3