Factor Out the Greatest Common Factor $5 x ^ { 2 } - 30 x$

Factor out the greatest common factor.
- $5 x ^ { 2 } - 30 x$

A) $5 x ( x - 6 x )$
B) $x ( 5 x - 30 )$
C) $5 x ( x - 6 )$
D) $5 \left( x ^ { 2 } - 6 x \right)$