On the set of positive integers, the operations $\oplus$ and $\otimes$ are defined using the greatest common divisor and least common multiple as follows:
$$\begin{aligned}
& a \oplus b = \operatorname { GCD } ( a , b ) \\
& a \otimes b = \operatorname { LCM } ( a , b )
\end{aligned}$$
Accordingly, what is the result of the operation $18 \oplus ( 12 \otimes 4 )$?\\
A) 2\\
B) 3\\
C) 6\\
D) 8\\
E) 9