Why Are Crimes Defined as Felony and Misdemeanors and Each

Why are crimes defined as felony and misdemeanors and each are further defined by classification?

A) It is a convenience designed by legislatures with little meaning
B) It is designed to determine which police agencies and courts deal with the offenders
C) It is a concerted effort to grade offenses according to the level of criminal culpability and the depth and breadth of criminal participation
D) The classifications are arbitrary and provide little explanation for the severity with which societies view criminal acts