From the equation ${\text{X}}_{\text{A}}=\frac{{\text{w}}_{\text{A}}}{{\text{W}}_{\text{A}}}\times \frac{{\text{W}}_{\text{B}}}{{\text{w}}_{\text{B}}}$  (here A is solute, B is solvent) the correct terms represents

Mole fraction in dilute binary solution:

${\text{X}}_{\text{A}}=\frac{{\text{w}}_{\text{A}}}{{\text{W}}_{\text{A}}}\times \frac{{\text{W}}_{\text{B}}}{{\text{w}}_{\text{B}}}$

Here ${\text{w}}_{\text{A}}=$  Mass of solute

${\text{W}}_{\text{A}}=$  Gram molecular mass of solute

${\text{w}}_{\text{B}}=$  Mass of solvent

${\text{W}}_{\text{B}}=$  Gram molecular mass of solvent.