Answer:
A. to show how knowledge influences people’s thoughts and actions
Explanation:
The main idea is about Dolphins. The 2 key details are how they take care of there babies and about their teeth.
This part of the excerpt seems to be correct as it reveals that the diet alone is responsible for his ninth birthday: "It had plenty of room to expand, thanks to the spare diet of the establishment; and perhaps to this circumstance may be attributed his having any ninth birth-day at all."
It means that the state cannot control everything although they may want to