If $X = \{4^n - 3n - 1 : n \in N\}$ and $Y = \{9(n - 1) : n \in N\}$, where $N$ is the set of natural numbers, then $X \cup Y$ is equal to

Question

( A ) $Y$
( B ) $N$
( C ) $Y-X$
( D ) $X$