Use Properties of Rational Exponents to Simplify the Expression $\left( 64 x ^ { 4 } y ^ { 4 } \right) ^ { 1 / 2 }$

Multiple Choice

Use properties of rational exponents to simplify the expression. Assume that any variables represent positive numbers.
- $\left( 64 x ^ { 4 } y ^ { 4 } \right) ^ { 1 / 2 }$

A) $32 x ^ { 2 } y ^ { 2 }$
B) $8 x ^ { 7 / 2 } y = / 2$
C) $8 \mathrm { x } ^ { 2 } \mathrm { y } ^ { 2 }$
D) $8 x ^ { 9 / 2 } y ^ { 9 / 2 }$