Simplify the Expression $$3 \sqrt [ 3 ] { a } + \sqrt [ 3 ] { 64 a }$$

Multiple Choice

Simplify the expression. Assume all variables represent positive real numbers.
- $$3 \sqrt [ 3 ] { a } + \sqrt [ 3 ] { 64 a }$$

A) $4 \sqrt [ 3 ] { 64 a }$
B) $12 \sqrt [ 3 ] { a }$
C) $3 \sqrt [ 3 ] { a } + \sqrt [ 3 ] { 64 a }$
D) $7 \sqrt [ 3 ] { a }$