Find the Square Root If It Is a Real Number $\sqrt { \frac { 1 } { 81 } }$

Multiple Choice

Find the square root if it is a real number, or state that the expression is not a real number.
- $\sqrt { \frac { 1 } { 81 } }$

A) 9
B) $\frac { 1 } { 9 }$
C) $\frac { 1 } { 6561 }$
D) 81