Which of the following organisms is viviparous?

Sheep is the organism that is viviparous. Viviparity is a mode of reproduction where the embryo develops inside the mother's body and is nourished through a placenta or a similar structure, and the offspring are born alive. Sheep are mammals and, like other mammals, give birth to live young ones that have been nourished inside the mother's body through a placenta. The other organisms listed are not viviparous, as tapeworms, snails, and grasshoppers are oviparous, meaning they lay eggs, and lizards are oviparous or ovoviviparous, meaning they lay eggs or retain the eggs inside their body until they are ready to hatch.