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: The formation of the complex called Aminophylline improves the solubility of one of the following drugs: 
 Options:  <1> Theophylline <2> Digoxin <3> Ampicillin <4> Thioridazine. <5> Ciclosporin
[EX A]: 1

[EX Q]: Question: Liquid chromatography in normal phase: 
 Options:  <1> It uses a column with apolar groups that interact with the apolar part of the analytes differentially. <2> It is a mode of operation that employs a polar stationary phase with a low polarity mobile phase. <3> It uses highly polar mobile phases such as alkanes or chloroalkanes. <4> It is a mode of operation that employs a non-polar surface with a mixed aqueous / organic mobile phase. <5> It uses stationary phases with a large number of hydrophobic alkyl ligands.
[EX A]: 2

[EX Q]: Question: In the quantitative analysis by gas chromatography, to minimize the uncertainties that are introduced with the injection of the sample, the flow velocity and the variations in the conditions of the columns is used: 
 Options:  <1> Manual estimation of chromatographic peak heights. <2> The normalization of the areas. <3> The method of standard additions. <4> An external calibration <5> The internal pattern method.
[EX A]:
5