Which of the following describes a major cultural achievement of the
classical Greek civilization?

The major cultural achievement of the Classical Greek civilization was the advancement of science and mathematics. Philosophy, architecture and literature also developed during this period.

Explanation:

The Greeks had scientific minds and were always searching for logic. Their scientific inquiries led to the invention of various astronomical instruments. The infamous Pythagoras Theorem was developed during this period. Philosophical thinking further made the Greeks think on rational lines and they only accepted facts that were proven logically. Some of the famous works of literature date back to the Classical Greek period. Also, the building they built were both strong and beautiful to look at. The designs are unique and one of a kind.

Ithink i know of the assessment that you're taking, and the answer is "freedom to meet peacefully."