Definition: 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'.
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.
