Answer : The correct option is, (a) specific
Explanation :
Mole fraction : Mole fraction of a constituent (solute as well as solvent) the fraction obtained by dividing the number of moles of that constituent by the total number of moles of all the constituents present in the solution. It is denotes as 'x'
And the sum of the mole fraction of the solvent and the solute is equal to '1'.



Hence, a mole or fraction of a mole represents a specific number of atoms or molecules.