Simplify
- $\sqrt [ 3 ] { 7 } \sqrt [ 3 ] { 147 }$

Multiple Choice

Simplify.
- $\sqrt [ 3 ] { 7 } \sqrt [ 3 ] { 147 }$

A) $3 \sqrt [ 3 ] { 7 }$
B) $$9 \sqrt [ 3 ] { 7 }$$
C) $7 \sqrt [ 3 ] { 3 }$
D) $21 \sqrt [ 3 ] { 3 }$