What was the purpose of the great wall of china?

select the best answer from the choices provided.

a) to keep out barbarians
b) to keep the chinese people from escaping
c) to keep out romans
d) to be a monument to the gods

The answer is A to keep out barbarians. they didn't want the mongolians invaiding them

Primary sources are usually  more accurate and are written by someone who experienced it or witnessed it. secondary sources are those who heard of it after the fact that can lose details and or twist the event in a light that benefits them.