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 diagnostic sensitivity of an analytical magnitude for a certain disease is: 
 Options:  <1> 1 / specificity. <2> It depends on the prevalence of the disease. <3> It is the number of patients that give positive results among all possible individuals. <4> It is the quotient between the number of patients who give positive results for this magnitude and the total number of patients considered. <5> It is deducted directly from the minimum detectable value of this magnitude.
[A]: 4


[Q]: Question: It has been proven that amphetamines have reinforcing effects because: 
 Options:  <1> They are GABAergic agonists. <2> They are dopaminergic antagonists. <3> They are serotonergic antagonists. <4> They are dopaminergic agonists. <5> They are serotonergic agonists.
[A]: 4


[Q]: Question: The phosphate groups of the nucleotides: 
 Options:  <1> They are stabilized by binding to divalent anions. <2> They form low-energy hydrolysis bonds. <3> They are called X, Y and Z as they move away from ribose. <4> They are attached to the C3' of the ribose. <5> They present negative charge.
[A]:
5