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

Multiple Choice

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

A) $\frac { \sec \alpha \sec \beta } { \cos ^ { 2 } \alpha - \sin ^ { 2 } \beta }$

B) $\frac { 1 } { \cos ^ { 2 } \alpha - \cos ^ { 2 } \beta }$

C) $\frac { \sec ^ { 2 } \alpha \sec ^ { 2 } \beta } { 1 - \tan ^ { 2 } \alpha \tan ^ { 2 } \beta }$

D) $\sec ^ { 2 } \alpha - \sec ^ { 2 } \beta$