In this task, you are given a question and a context passage. You have to answer the question based on the given passage.

[EX Q]: Besides sheriffs and posses, who helped keep the peace?, Context: In the American Old West, policing was often of very poor quality.[citation needed] The Army often provided some policing alongside poorly resourced sheriffs and temporarily organized posses.[citation needed] Public organizations were supplemented by private contractors, notably the Pinkerton National Detective Agency, which was hired by individuals, businessmen, local governments and the federal government. At its height, the Pinkerton Agency's numbers exceeded those of the United States Army.[citation needed]
[EX A]: Army

[EX Q]: Which of the following did not occur in the 20th century: urbanization, the spread of the Ottoman Empire, or wars?, Context: South Slavic historically formed a dialect continuum, i.e. each dialect has some similarities with the neighboring one, and differences grow with distance. However, migrations from the 16th to 18th centuries resulting from the spread of Ottoman Empire on the Balkans have caused large-scale population displacement that broke the dialect continuum into many geographical pockets. Migrations in the 20th century, primarily caused by urbanization and wars, also contributed to the reduction of dialectal differences.
[EX A]: spread of Ottoman Empire

[EX Q]: Why is the repulsive force between two fermionic particles called a normal force?, Context: The normal force is due to repulsive forces of interaction between atoms at close contact. When their electron clouds overlap, Pauli repulsion (due to fermionic nature of electrons) follows resulting in the force that acts in a direction normal to the surface interface between two objects.:93 The normal force, for example, is responsible for the structural integrity of tables and floors as well as being the force that responds whenever an external force pushes on a solid object. An example of the normal force in action is the impact force on an object crashing into an immobile surface.
[EX A]:
the force that acts in a direction normal to the surface interface between two objects