Find a Formula for the Nth Partial Sum of the Series

Multiple Choice

Find a formula for the nth partial sum of the series and use it to find the series' sum if the series converges.
- $$3 - 24 + 192 - 1536 + \ldots + ( - 1 ) ^ { n - 1 } 3 \cdot 8 ^ { n - 1 } + \ldots$$

A) $\frac { 3 \left( 1 - ( - 8 ) ^ { n } \right) } { 1 - 8 } ; \frac { 3 } { 7 }$
B) $\frac { 3 \left( 1 - ( - 8 ) ^ { n } \right) } { 1 + 8 }$ ; series diverges
C) $\frac { 3 \left( 1 - ( - 8 ) ^ { n } \right) } { 8 - 1 } ;$ series diverges
D) $\frac { 3 \left( 1 - ( - 8 ) ^ { n } \right) } { 1 + 8 } ; \frac { 1 } { 3 }$