Factor Completely $$5 x ^ { 5 } + 20 x ^ { 4 } - 105 x ^ { 3 }$$

Multiple Choice

Factor completely. If the polynomial cannot be factored, write ʺprime.ʺ
- $$5 x ^ { 5 } + 20 x ^ { 4 } - 105 x ^ { 3 }$$

A) $x ^ { 3 } ( 5 x - 15 ) ( x + 7 )$
B) $5 x ^ { 3 } ( x - 3 ) ( x + 7 )$
C) $5 x ^ { 3 } \left( x ^ { 2 } + 4 x - 21 \right)$
D) $x ^ { 3 } ( x - 3 ) ( 5 x + 35 )$