Use the Product Rule to Multiply $\sqrt [ 5 ] { 5 x ^ { 4 } } \cdot \sqrt [ 5 ] { 81 }$

Multiple Choice

Use the product rule to multiply. Assume all variables represent positive real numbers.
- $\sqrt [ 5 ] { 5 x ^ { 4 } } \cdot \sqrt [ 5 ] { 81 }$

A) $405 x ^ { 4 }$
B) $9 x ^ { 2 }$
C) $\sqrt { 405 x ^ { 4 } }$
D) $\sqrt [ 5 ] { 405 x ^ { 4 } }$