*[Choose the one correct answer and explain your reasoning.]*

The circle in the diagram has centre \(C\). Three angles \(\alpha, \beta, \gamma\) are also indicated.

The angles \(\alpha,\beta, \gamma\) are related by the equation:

\(\cos \alpha = \sin (\beta + \gamma)\),

\(\sin \beta = \sin \alpha \sin \gamma\),

\(\sin \beta (1 − \cos \alpha) = \sin \gamma\),

\(\sin (\alpha + \beta) = \cos \gamma \sin \alpha\).