Answer:
a. Felonies
Explanation:
Most serious violent crimes are considered felonies, that's the opposite of misdemeanors which are for crimes of lesser importance. Both are related because they speak of the severity of the crimes.
The other two don't tell anything about the severity of the crime, but rather about who committed the crime. Blue-collar crimes are the crimes committed by low-class workers, like plant workers, drivers and such. White-collar crimes are the crimes committed by people with higher working class, like bosses or company executives.
