How long has the constitution been in effect?

the constitution was signed September 17th, 1787. so 2018 - 1787 = 231 years

It was In effect from September 17 1787, They talked about singing it at the Constitutional Convention, This means they got rid of The Confederation.

b. martin luther king jr. wrote and spoke "i have a dream"

explanation:

i know this 100 percent is correct   b. is the best one. < 3

c. troops marched forward in close formation against newer, more accurate weapons