Simplify the Expression $$4 \sqrt [ 3 ] { a } + \sqrt [ 3 ] { 8 a }$$

Multiple Choice

Simplify the expression. Assume all variables represent positive real numbers.
- $$4 \sqrt [ 3 ] { a } + \sqrt [ 3 ] { 8 a }$$

A) $5 \sqrt [ 3 ] { 8 a }$
B) $6 \sqrt [ 3 ] { a }$
C) $4 \sqrt [ 3 ] { a } + \sqrt [ 3 ] { 8 a }$
D) $8 \sqrt [ 3 ] { a }$