Multiply the Radical Expressions and Simplify Your Answer $\sqrt { 5 x ^ { 3 } } \cdot \sqrt { 18 x ^ { 6 } }$

Multiple Choice

Multiply the radical expressions and simplify your answer. $\sqrt { 5 x ^ { 3 } } \cdot \sqrt { 18 x ^ { 6 } }$

A) $3 \sqrt { 10 x ^ { 9 } }$
B) $\sqrt { 30 x ^ { 9 } }$
C) $3 x ^ { 4 } \sqrt { 10 x }$
D) $9 x ^ { 4 } \sqrt { 10 x }$