Factor by Grouping $15 a ^ { 3 } + 9 a ^ { 2 } b + 25 a b ^ { 2 } + 15 b ^ { 3 }$

Multiple Choice

Factor by grouping.
- $15 a ^ { 3 } + 9 a ^ { 2 } b + 25 a b ^ { 2 } + 15 b ^ { 3 }$

A) $\left( 15 a ^ { 2 } + 5 b ^ { 2 } \right) ( a + 3 b )$
B) $\left( 3 a ^ { 2 } - 5 b ^ { 2 } \right) ( 5 a - 3 b )$
C) $\left( 3 a ^ { 2 } + 5 b \right) ( 5 a + 3 b )$
D) $\left( 3 a ^ { 2 } + 5 b ^ { 2 } \right) ( 5 a + 3 b )$