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'.

[EX Q]: Question: What specific procedure of the experimental strategy makes it the most appropriate to test hypotheses of causality? : 
 Options:  <1> The representative sampling of the participants. <2> The manipulation of the independent variable with control of possible strange variables. <3> The realization of the study in real contexts with natural groups. <4> The identification of possible predictor variables through the retrospective analysis of the study phenomenon. <5> The application of statistical techniques for the analysis of data.
[EX A]: 2

[EX Q]: Question: To detect the occurrence of prerenal acute renal failure in a patient, the nurse should monitor the presence of: 
 Options:  <1> Signs of low cardiac output. <2> Hematuria <3> Urine cloudy and smelly. <4> Colic pain <5> Elevation of creatinine clearance.
[EX A]: 1

[EX Q]: Question: The lithium dialkyl-heptarate reacts with alkyl halides to produce, by formation of carbon-carbon bonds between the alkyl group of the halide and the alkyl group of the dialkyl acetate: 
 Options:  <1> Alcanes. <2> Alquenos <3> Alquinos. <4> Aromatics <5> Piranos.
[EX A]:
1