38-40
      The tactics used to control riots in the past were simple -- they were based on the fact that the police were almost always better-armed than the rioters. The tactics they used basically consisted of forming a line and charging into the crowd. Today's riot control units are usually called crowd-management units, and just try to calm people down and get them to go home. The tactics have advanced significantly in hopes of preventing injuries. The use of force, even non-lethal force, is a last resort.
      When a riot is in full swing, police will deploy in a square formation with a command team at the center. This tactical unit is very mobile and able to adapt on the fly to changes in the situation. If a threat suddenly appears behind or to one side of the unit, then the echelon facing that direction is designated the front of the unit. The entire team can then change the direction it's facing without a lot of maneuvering. If a particularly violent group moves toward the officers or they spot specific suspects they want to arrest, they can quickly close the gaps and form a tight line.
38. According to the passage, the aim of today's riot-control is
(A) trying to beat or shoot the rioters into submission
(B) trying to get people to go home and prevent injuries
(C) trying to form a line and charge into the rioter
(D) trying to change the direction it's facing