Given that $\alpha , \beta \in \left[ 0 , \frac { \pi } { 2 } \right]$,
$$\sin ( \alpha - \beta ) = \sin \alpha \cdot \cos \beta$$
Which of the following is true?\\
A) $\alpha = 0$ or $\beta = \frac { \pi } { 2 }$\\
B) $\alpha = 0$ or $\beta = \frac { \pi } { 4 }$\\
C) $\alpha = \frac { \pi } { 2 }$ or $\beta = 0$\\
D) $\alpha = \frac { \pi } { 2 }$ or $\beta = \frac { \pi } { 2 }$\\
E) $\alpha = \frac { \pi } { 4 }$ or $\beta = 0$