Simplify and Write with Positive Exponents Only $\left( 9 x ^ { - 7 } \right) \left( 7 x ^ { - 5 } \right)$

Multiple Choice

Simplify and write with positive exponents only.
- $\left( 9 x ^ { - 7 } \right) \left( 7 x ^ { - 5 } \right)$

A) 63 x¹²
B) 63 x³⁵
C) -63 x³⁵
D) $\frac { 63 } { x ^ { 12 } }$