The people who have inhabited central america the longest are the a spaniards b europeans c indians d africans

C Indians is your best answer.

The Native Americans that were located in Central America were commonly called "Indians", for the Spaniards mistaken the West for the Asia's, in which Europeans were trying to find a sea route too.

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b) race riots in several cities

when world war i broke out across europe in 1914, president woodrow wilson proclaimed the united states would remain neutral, and many americans supported this policy of nonintervention. however, public opinion about neutrality started to change after the sinking of the british ocean liner lusitania by a german u-boat in 1915; almost 2,000 people perished, including 128 americans. along with news of the zimmerman telegram threatening an alliance between germany and mexico, wilson asked congress for a declaration of war against germany. the u.s. officially entered the conflict on april 6, 1917.