Which of the following is true based on the given figure ?

Question

$\begin{array}{1 1} (a)\;\sin \large\frac{\pi}{6}=\frac{15}{25} \\ (b)\;\sin \large\frac{\pi}{6}=\frac{20}{26} \\ (c)\;\cos \large\frac{\pi}{6}=\frac{20}{25} \\ (d)\;\cos \large\frac{\pi}{6}=\frac{15}{25} \end{array}$