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'.

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.
2

Question: If you want to estimate the effects of an intervention, you will use: 
 Options:  <1> A transversal design. <2> A retrospective design <3> An ecological study. <4> A randomized clinical trial. <5> An observational design with random selection of the participants.
4

Question: NOT true about Rheumatoid Arthritis: 
 Options:  <1> Early diagnosis, intensive treatment and close control of the disease are essential. <2> Methotrexate is the drug of first choice to control the activity of the disease. <3> The rheumatoid factor is typical of the disease and is a mandatory criterion for diagnosis. <4> The specificity of citrullinated peptide antibodies is very high and has a prognostic value. <5> Biological drugs, such as anti TNF, have revolutionized the treatment.

3