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'.

Ex Input:
Question: Sodium metal reacts violently with water because Na:
Options: <1> Oxidize the water to oxygen, and the reaction is very exothermic. <2> It reduces the water to hydrogen, and the reaction is very exothermic. <3> Oxidizes the water to oxygen, and when a gas is generated, the entropy increases enormously. <4> It reduces the water to hydrogen, and the reaction is very endothermic. <5> It combines with water giving rise to an explosive hydride.

Ex Output:
2

Ex Input:
Question: What speed of perfusion of a drug should you administer to achieve a plasma equilibrium concentration of 10 mg / L knowing that it has a plasma clearance of 500 mL / h? (continuous perfusion):
Options: <1> 50 mg / h. <2> 5 mL / h. <3> 100 mg / h. <4> 100 mg / mL. <5> 5 mg / h.

Ex Output:
5

Ex Input:
Question: The solubility of calcium fluoride in a solution of pH <3 is higher than in pure water due to:
Options: <1> The absence of reactions of formation of hydroxylated calcium complexes at these pH values. <2> The lower hydration capacity of the precipitate particles at these pH values. <3> The absence of reactions of formation of soluble complexes of calcium and fluoride at these pH values. <4> The complex formation reactions of the Ca2 + ion with the hydronium. <5> The protonation reaction of the fluoride anion.

Ex Output:
5