Among the list given hen is odd one out "Human being, cow, dog, hen". The reason for this is

Question

$\begin{array}{1 1} (a)\; \text{It undergoes internal fertilization } \\ (b)\; \text{It is oviparous} \\ (c)\; \text{It is viviparous} \\ (d)\; \text{It undergoes external fertilization} \end{array}$