Use the Formula for the Cosine of the Difference of Two

Multiple Choice

Use the Formula for the Cosine of the Difference of Two Angles
- $\cos \left( 165 ^ { \circ } \right) \cos \left( 45 ^ { \circ } \right) + \sin \left( 165 ^ { \circ } \right) \sin \left( 45 ^ { \circ } \right)$

A) $\alpha = 165 ^ { \circ } , \beta = 45 ^ { \circ }$
B) $\alpha = - 165 ^ { \circ } , \beta = 45 ^ { \circ }$
C) $\alpha = - 45 ^ { \circ } , \beta = 165 ^ { \circ }$
D) $\alpha = 45 ^ { \circ } , \beta = 165 ^ { \circ }$