How Did Police Respond to the Protesters Outside the Democratic

How did police respond to the protesters outside the Democratic National Convention in Chicago on August 28, 1968?

A) They merely secured the perimeters and prevented looting of neighborhood stores.
B) Mostly Republicans themselves, the police deliberately allowed protesters to enter the convention hall.
C) The police clubbed and tear-gased the demonstrators outside the Hilton Hotel in downtown Chicago.
D) Understanding the common grievances, many police officers joined the ranks of the protesters.