If $${\log _x}\left( {\frac{9}{{16}}} \right) =- \frac{1}{2},$$then x is equal to:

If $${\log _x}\left( {\frac{9}{{16}}} \right) =- \frac{1}{2},$$then x

1.	If $${\log _x}\left( {\frac{9}{{16}}} \right) =- \frac{1}{2},$$then x is equal to:
A.	$ - \frac{3}{4}$$
B.	$\frac{3}{4}$$
C.	$\frac{{81}}{{256}}$$
D.	$\frac{{256}}{{81}}$$
Answer» E.