The diagram illustrates the refraction of a ray of light as it passes from air into Perspex. The critical angle of Perspex is $c$. Which expression is correct?
- A$\frac{\sin x}{\sin z} = \sin c$
- B$\frac{\sin z}{\sin x} = \sin c$
- C$\frac{\sin w}{\sin y} = \sin c$
- D$\frac{\sin y}{\sin w} = \sin c$