Most of what we know about the Olmec civilization comes from A.
their books and writings.
B.
the stories of Aztec historians.
C.
the diaries of Spanish explorers.
D.
their sculptures and artifacts.

Their sculptures and artifacts.

Explanation:

The Olmecs were extremely talented artists and sculptors: they produced many statues, masks, figurines (Yes, figurines were a thing back then), stelae (I know you're confused. A stela (the singular form of stelae) is an upright stone or column typically bearing a commemorative inscription or relief design, often serving as a gravestone.), thrones and more. However, they are best known for their colossal heads, 17 of which have been found at four different archaeological sites.

The first picture is an Olmec head, and the second is a stela.

the noble might have thought that the system was far because they had lot of things and riches and the serf would have thought that the feudal system was un fair because of the way they were treated.

answer: ensure protection from communism

explanation:

the north atlantic treaty was largely dormant until the korean war initiated the establishment of nato to implement it, by means of an integrated military structure: this included the formation of supreme headquarters allied powers europe in 1951, which adopted the western union's military structures and plans.