Use a Sum or Difference Identity to Find the Exact $\sin \frac { 7 \pi } { 24 } \cos \frac { \pi } { 8 } - \cos \frac { 7 \pi } { 24 } \sin \frac { \pi } { 8 }$

Multiple Choice

Use a sum or difference identity to find the exact value.
- $\sin \frac { 7 \pi } { 24 } \cos \frac { \pi } { 8 } - \cos \frac { 7 \pi } { 24 } \sin \frac { \pi } { 8 }$

A) $\frac { 1 } { 2 }$
B) $\frac { \sqrt { 2 } } { 2 }$
C) 1
D) $\frac { \sqrt { 3 } } { 2 }$