Herbivores are animals that feed only on plants, while carnivores are animals that feed only on other animals. Let's analyze each pair and determine if they consist of a herbivore and a carnivore.

a) Goat and deer
- Both goats and deer are herbivores. They primarily feed on vegetation such as grass, leaves, and fruits. Therefore, this pair does not consist of a herbivore and a carnivore.

b) Deer and crocodile
- Deer is a herbivore, as mentioned earlier. It feeds on plants and vegetation.
- Crocodile, on the other hand, is a carnivore. It preys on other animals, including fish, birds, and mammals.
Therefore, this pair consists of a herbivore (deer) and a carnivore (crocodile).

c) Bear and tiger
- Bears are omnivores, which means they eat both plants and animals. While they mainly feed on vegetation such as berries, nuts, and grass, they can also consume meat.
- Tigers are carnivores. They primarily hunt and feed on other animals.
Although bears can occasionally consume meat, they are not classified as strict carnivores like tigers. Therefore, this pair does not consist of a herbivore and a carnivore.

d) Tiger and eagle
- Tigers, as mentioned earlier, are carnivores. They are apex predators and solely rely on other animals for their nutrition.
- Eagles are also carnivores. They predominantly feed on small mammals, birds, and fish.
This pair consists of two carnivores (tiger and eagle), and not a herbivore and a carnivore.

In conclusion, the correct pair consisting of a herbivore and a carnivore is option B, which includes a deer (herbivore) and a crocodile (carnivore).