The correct answer is the following: option B. The most important effect of the Peloponnesian War was the fact that other nations saw Greece's lack of unification as weak.
The Peloponnesian War was the armed conflict between Sparta its allies and Athens and its allies to gain control over Athens. It lasted 27 years and in the end Athens lost the battle, but in fact, after more than 25 years of continuous battle, every city-state of Greece was deeply affected and weakened as a result of the war. The lack of unity of the Nation was a sign of weakness for other nations that used to hold Greece as a power and example of unity and government structure.
