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: Which of the following enzyme complexes catalyzes the reduction of molecular oxygen to water during oxidative phosphorylation? 
 Options:  <1> ATP synthase. <2> Cytochrome c oxidase. <3> NADH-Q oxide-reductase. <4> Q-cytochrome c-oxide-reductase. <5> Succinate-Q reductase.
[A]: 2


[Q]: Question: Which of the following situations would noticeably decrease the transcription of a gene? 
 Options:  <1> The presence of a repressor and an inducing molecule. <2> The binding of RNA polymerase to DNA. <3> The presence of a repressor and a correpressor molecule. <4> The presence of an activator and its signal molecule. <5> The presence of a mutated repressor that could not bind to DNA.
[A]: 3


[Q]: Question: Which of the following characteristics defines an endogenous depression? 
 Options:  <1> Its course is continuous. <2> There is an evening worsening. <3> There is an early awakening. <4> There is a good response to placebo. <5> A neurotic personality intervenes in the etiopathogenesis.
[A]:
3