Final answer:
The farmer already knows that he has 13 animals, and that is enough information to determine the number of types of animals. The question does not ask for the specific types of animals, only the information needed to determine them.
Step-by-step explanation:
d) None, 13 is enough information. The farmer already knows that he has 13 animals, and that is enough information to determine the number of types of animals. The question does not ask for the specific types of animals, only the information needed to determine them. In this case, the given information of the number of animals is sufficient to answer the question.
For example, if the farmer has 10 cows and 3 horses, the information about the number of animals (13) would be enough to determine that there are 2 types of animals on the farm (cows and horses).