In order to convert from odd to probability, we can use the formula below:
[tex]odd=\frac{a}{b}\rightarrow p=\frac{a}{a+b}[/tex]So, if the odd of the horse winning is 8:5, the probability is:
[tex]p=\frac{8}{8+5}=\frac{8}{13}[/tex]Therefore the correct option is D.
