The federal government supported the land offer
made in this advertisement by
(1) encouraging exploration for gold and silver
(2) creating a sharecropping system after the
Civil War
(3) protecting the hunting grounds of Native
American Indians
(4) giving public land to railroad companies to
help finance railroad construction
Assuming this is referring to the same picture that was posted before with this question, the proper answer is "(4) giving public land to railroad companies to help finance railroad construction"