What type of historical skill do you use to put things in the proper order

Which fact would this be, and how might you verify the truth?

To encourage railroad companies to build railroads across the west, the government gave them subsidies by select the best answer from the choices provided. a. paying the wages of laborers b. giving them building materials c. providing railroad trains d. providing free land

What were the four terms that american had to agree in order to live in mexico texas