Simplify the Expression $2 ^ { 6 } \cdot 2 ^ { 3 }$

Multiple Choice

Simplify the expression. Assume all variables represent nonzero real numbers.
- $2 ^ { 6 } \cdot 2 ^ { 3 }$

A) $2^{9}$
B) $4^{18}$
C) $2^{18}$
D) $4^{9}$