Complete the Identity $\cos ( \alpha + \beta ) \cos ( \alpha - \beta ) =$

Complete the identity.
- $\cos ( \alpha + \beta ) \cos ( \alpha - \beta ) =$ ?

A) $\cos \left( \alpha ^ { 2 } \right) \cos \left( \beta ^ { 2 } \right) + \sin \left( \alpha ^ { 2 } \right) \sin \left( \beta ^ { 2 } \right)$
B) $2 - \sin ^ { 2 } \alpha - \sin ^ { 2 } \beta$
C) $\cos ^ { 2 } \beta - 2 \sin ^ { 2 } \alpha \sin ^ { 2 } \beta$
D) $\cos ^ { 2 } \beta - \sin ^ { 2 } \alpha$