$$Blue=\frac{1}{4}=\frac{6}{24}$$ $$Purple=\frac{1}{8}=\frac{3}{24}$$ $$Green=\frac{1}{12}=\frac{2}{24}$$ $$Orange=\frac{3}{8}=\frac{9}{24}$$ $$Red=\frac{1}{6}=\frac{4}{24}$$

The chance of stopping in green is the lowest.