According to the Historian Thucydides,the Peloponnesian War Began

According to the historian Thucydides,the Peloponnesian War began:

A) as a way to permanently remove the Persian threat from the Aegean Sea.
B) because of the growing power of Athens, and the fear and envy this power inspired in Sparta.
C) to facilitate the expansion of Athens into Syracuse (Sicily) .
D) because Athens failed to support the Delian League.
E) when Sparta's imperial ambitions threatened the Greeks north of the Peloponnesus.