What does the word promotion mean with in the context of this article

Why might carl sandburg have placed an emphasis on politeness among the animals in the committee of sixty six and in the interactions the animals have with humans in "how the animals lost their tails and got them back traveling from philadelphia to medicine hat"? a. to show that animals are more polite than humans b. to poke fun at the extreme politeness of the animals c. to teach children how to interact with adults d. to teach children how to interact with animals asap