What signifies the period known as history?
a. there are written records.
b. it is a much longer period than prehistory.
c. it started two million years ago.
d. it started two centuries ago.

I believe the correct answer is "There are written records"

i don't get what you mean

explanation:

in february 1787, congress decided that a convention should be convened to revise the articles of confederation, the nation’s first constitution. in may, 55 delegates came to philadelphia, and the constitutional convention began. debates erupted over representation in congress, over slavery, and over the new executive branch. the debates continued through four hot and muggy months. but eventually the delegates reached compromises, and on september 17, they produced the u.s. constitution, replacing the articles with the governing document that has functioned effectively for more than 200 years.