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: 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.
[A]: 4

[Q]: Question: In the -oxidation of odd-chain fatty acids, what is the molecule that forms with the last three carbons to enter the citric acid cycle ?:
Options: <1> Propionyl-CoA. <2> Methylmalonyl-CoA. <3> Succinyl-CoA. <4> Succinate <5> Malate.
[A]: 3

[Q]: Question: The carboxypeptidases A and B:
Options: <1> They are endopeptidases. <2> They are excreted by exocrine cells of the intestine. <3> They are excreted by exocrine cells of the stomach. <4> They are synthesized by endocrine cells of the liver. <5> They are synthesized by exocrine cells of the pancreas.
[A]:
5