The horse, $\textit{Equus ferus}$, and the donkey, $\textit{Equus asinus}$, can interbreed. Their offspring is known as a mule. Which statement is correct?
- AThe horse and the donkey are the same genus; the mule is infertile.
- BThe horse and the donkey are the same species; the mule is infertile.
- CThe horse and the donkey are the same genus; the mule is fertile.
- DThe horse and the donkey are the same species; the mule is fertile.