Which sentence is the topic sentence?

A、When you were younger, your mother cautioned you not to act like an animal.
B、 What mother did not realize is that much of the world holds animals in such high regard that they use animals' names for their organizations and products.
C、 For instance, many professional sports teams, such as the Tigers and the Rams, have chosen animal names to suggest power.
D、 Also, cars are given names to make consumers associate them with speed and grace.
E、 Examples are the Jaguar, the Cougar, and the Bobcat.
F、 Even our political parties have adopted animals to represent them.