the power to create and maintain a police force which is exercised at the state and local lever, is considered

D- Reserved powers

Explanation:

According to the Constitution of the United States, the 10th amendment grants powers not delegated to the Federal Government to the states. These powers are not written down or 'enumerated'. But they are powers that are meant to protect the health,safety and welfare of the states residents. Thus a local police force , it's creation and maintenance would fall under the 'reserved powers' of the states.

answer; decipher the motives for why people behave the way they do;