What is the best answer

Answer:
(1/2 x - 1/3y)(1/4 x^2 + 1/6x + 1/9 x^2)
Step-by-step explanation:
Using the identity a^3 - b^3 = (a - b)(a^2 + ab + b^2):-
1/8x^3 - 1/27y^3 (here a = cube root of 1/8x^3 = 1/2 x and b = 1/3 y) so:-
= (1/2 x - 1/3y ) ( 1/4x^2 + 1/2x * 1/3y + 1/9y^2)
= (1/2 x - 1/3 y)(1/4 x^2 + 1/6 x + 1/9 x^2)