Answer:
Correct answer is A . Later societies carried on some Olmec traditions.
Explanation:
Although their culture disappeared it is obvious that they impacted a lot some that came later, especially when it comes to their beliefs. Therefore A is correct.
B is not correct as they continued to live through other civilizations, although their own civilization was not known to us until 19th Century.
C is totally false as they had their governing system, but also social hierarchy.
D is not correct as Olmecs are actually the first major Mesoamerican civilization.