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: They can be part of the B lymphocyte receptor on the cell surface:
Options: <1> IgM and IgG. <2> IgD and IgG. <3> IgD and IgM. <4> IgA and IgM. <5> IgG and IgE.
[A]: 3

[Q]: Question: The eudismic index is a parameter with pharmacological interest that expresses the relationship between:
Options: <1> Two diastereomer drugs. <2> Two bioisostero drugs. <3> Two enantiomers <4> A drug and a prodrug, structural analog. <5> Two structural modifications, one hydrophilic and one lipophilic, of a certain drug.
[A]: 3

[Q]: Question: In what clinical situation would you use a combined antimicrobial treatment?
Options: <1> In an acute pharyngotonsillitis in a child. <2> In a community pneumonia due to Mycoplasma pneumoniae in a teenager. <3> In an acute meningitis in an elderly patient. <4> In a postmenopausal patient with a recurrent urinary infection. <5> In a skin abscess in a young patient.
[A]:
3