Factor Assume That Variables Used as Exponents Represent Positive Integers $$7 x ^ { 2 n } + 5 x ^ { n } - 18$$

Multiple Choice

Factor. Assume that variables used as exponents represent positive integers.
- $$7 x ^ { 2 n } + 5 x ^ { n } - 18$$

A) $\left( \mathrm { x } ^ { \mathrm { n } } - 9 \right) \left( 7 \mathrm { x } ^ { \mathrm { n } } + 2 \right)$
B) $\left( x ^ { n } + 2 \right) \left( 7 x ^ { n } - 9 \right)$
C) $\left( x ^ { n } - 2 \right) \left( 7 x ^ { n } + 9 \right)$
D) prime polynomial