Find the Indicated Term of the Binomial Expansion $\left( 2 r - s ^ { 2 } \right) ^ { 9 }$

Multiple Choice

Find the indicated term of the binomial expansion. $\left( 2 r - s ^ { 2 } \right) ^ { 9 }$ ; seventh

A) $168 r ^ { 3 } s ^ { 6 }$
B) $- 72 r ^ { 2 } s ^ { 7 }$
C) $- 144 r ^ { 2 } s ^ { 14 }$
D) $672 r ^ { 3 } s ^ { 12 }$