The sentence that is an example of states serving as “laboratories of democracy” is option B. Different states having different policies and regulations regarding what age people can vote.
In America for instance, the 50 states are also called “laboratories of democracy” because they engineer creative policy ideas that are tested within the state and sometimes adopted at the federal level.
Therefore, option B. Different states having different policies and regulations regarding what age people can vote depicts the assertion.
learn more about laboratories of democracy: https://brainly.com/question/14446753
#SPJ1