How did conquering the Greek city-states achieve Philip II’s goal for Macedonia?

He wanted to spread Macedonia’s religion.
He wanted Macedonia to have more power.
He wanted Macedonia to have access to trade routes.
He wanted to improve Macedonia’s educational system.

The correct answer is He wanted Macedonia to have more power.

Philip II was king of Macedonia. He created the "Macedonian phalanx" - infantry that became fundamental to the achievements of his son Alexander the Great.

Under his rule, Macedonia widened its borders, making it the most important state on the Balkan peninsula.

Athens was not justified in using the money and resources of the league to build its navy and attack other city-states; the reason why Athens was not justified was because it (Athens) was also a member of the body of Greek city-states—known as the Delian League—which had a lot of successes over the Persians. On the other hand, the members of the league can be blamed for their situation because they opted to leave the Delian League which was powerful because of the navy that was controlled by Athens; the decision of the city-states to leave the League, prompted Athens to forcefully subdue and control the city-states/members of the League.