The volumes of two spheres are in a ratio of 1: 8. what is the ratio of their radii?

We know that

volume of a sphere=(4/3)*pi*r³

let
A> smaller sphere
B> larger sphere

VA=(4/3)*pi*rA³
VB=(4/3)*pi*rB³
VA/VB=1/8> (1/8)=[(4/3)*pi*rA³]/[(4/3)*pi*rB³]

 (1/8)=[rA³]/[rB³]> (1/8)=[rA/rB]³> rA/rB=∛(1/8)> rA/rB=1/2

the answer is
the ratio of their radii is (1/2)

Ithink it’s b, hope this .