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 are directly involved in allergic reactions:
Options: <1> T lymphocytes. <2> Dendritic cells <3> Monocytes <4> Platelets. <5> Mastocytes
[A]: 5

[Q]: Question: The proportion of environmental variance due to the influences that a person receives from their family environment and that are shared by the rest of their family:
Options: <1> It is the specific variance. <2> It is called genotypic variance. <3> It matches the heritability. <4> It is dismissed in the investigations. <5> It is the variance coming from the shared environment.
[A]: 5

[Q]: Question: What do behavioral treatments for major depressive disorder have in common?
Options: <1> The use of exposure techniques to stressful situations. <2> The main objective of modifying maladaptive beliefs and assumptions that make a person vulnerable to depression. <3> Which are unstructured therapies and without a limited number of sessions. <4> The main objective of increasing the positive reinforcement received by the depressed person. <5> The main objective of relating depression to problematic interpersonal situations.
[A]:
4