Simplify the Radical Expression $\sqrt { 567 x ^ { 2 } }$

Multiple Choice

Simplify the radical expression. Assume all variables represent positive real numbers.
- $\sqrt { 567 x ^ { 2 } }$

A) $567 x$
B) $9 \sqrt { 7 x }$
C) $9 x \sqrt { 7 }$
D) $7 x ^ { 2 } \sqrt { 9 }$