Two rules come in handy here:
- [tex]\dfrac{a^m}{a^n}=a^{m-n}[/tex]
- [tex]\sqrt[c]{x^r}=x^{\frac{r}{c}}[/tex]
So we have
[tex]
\dfrac{\sqrt[4]{6}}{\sqrt[5]{6}}=\dfrac{6^{\frac{1}{4}}}{6^{\frac{1}{5}}}=6^{1/4-1/5}=\boxed{6^{9/20}}
[/tex]
The answer is B.
Hope this helps.
