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'.

[Q]: Question: The main pharmacological treatment for obsessive-compulsive disorder or OCD is: 
 Options:  <1> Dopamine agonists. <2> NMDA receptor blockers. <3> Inhibitors of monoamine oxidase or MAOIs. <4> Selective serotonin or 5-HT reuptake inhibitors. <5> Neuroleptics
[A]: 4


[Q]: Question: With regard to pyrogens and biotechnological medicines, it is possible to say: 
 Options:  <1> They have no tendency to aggregate or form large units with high molecular weight. <2> Ion exchange chromatography procedures (using their positive charge) can reduce endotoxin levels. <3> Ion exchange chromatography procedures (using their negative charge) can reduce endotoxin levels. <4> Ion exchange chromatography procedures (regardless of their charge) can reduce endotoxin levels. <5> They are unstable under standard autoclaving conditions.
[A]: 3


[Q]: Question: In the elderly the total body water: 
 Options:  <1> It is half that in the adult. <2> It decreases fundamentally at the expense of the intravascular compartment. <3> It decreases mainly due to the reduction of extracellular fluid. <4> It decreases greatly as a result of the loss of muscle mass. <5> It represents 30% of body weight.
[A]:
4