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: To detect the occurrence of prerenal acute renal failure in a patient, the nurse should monitor the presence of: 
 Options:  <1> Signs of low cardiac output. <2> Hematuria <3> Urine cloudy and smelly. <4> Colic pain <5> Elevation of creatinine clearance.
[A]: 1


[Q]: Question: In the process of maturation of the affinity of the B lymphocytes in the germinal centers, they act as accessory cells: 
 Options:  <1> Macrophages <2> Th1 lymphocytes. <3> Mastocytes <4> Follicular dendritic cells. <5> Langerhans cells.
[A]:
4