which of the following were the causes of the peloponnesian war? select the three correct answers.
a.
athens was afraid of sparta's alliance because they did not have one.
b.
sparta did not trust the athenian democratic government.
c.
athens banned trade with a member of the peloponnesian league.
d.
sparta led forces that surrounded athens.
e.
sparta refused athens' invitation to join the delian league.