Factor, Using the Given Factor $$x ^ { - 7 } - 3 x ^ { - 3 } ; \quad x ^ { - 7 }$$

Multiple Choice

Factor, using the given factor. Assume all variables represent positive real numbers.
- $$x ^ { - 7 } - 3 x ^ { - 3 } ; \quad x ^ { - 7 }$$

A) $x ^ { - 7 } \left( 1 - 3 x ^ { 4 } \right)$
B) $x ^ { - 7 } \left( x - 3 x ^ { 4 } \right)$
C) $x ^ { - 7 } \left( x - 3 x ^ { 5 } \right)$
D) $x ^ { - 7 } \left( 1 + 3 x ^ { 6 } \right)$