I got the answer as letter C, can someone check me to make sure that is correct? Thank you in advance.

Answer:
The x's cancel so definitely is choice C: 1/9
Step-by-step explanation:
We have root( 1/(x^2) ) * root ((x^2) / 81)
simplifying this we get as follows:
root( 1/(x^2) ) * root ((x^2) / 81)
= [tex]\sqrt{(1/x^2 )}[/tex] * [tex]\sqrt{(x^2)/81}[/tex]
= ( 1/x ) * (x/9)
the x's cancel
= 1/9
choice C 1/9