How did persian rulers oversee such vast empire?

a. by organizing the empire into provinces administered by satraps
b. by destroying roads and bridges to keep communities isolated
c. by sending zoroastrian priests to convert conquered peoples
d. by permitting independent elected governments in distant towns and villages

The correct answer is
a. by organizing the empire into provinces administered by satraps

The satrapies could often keep their religion and their culture as long as they swore obedience to the Persian emperor. It often happened that after the death of the emperor some Satrapies would want to become independent or take control over the remainder of the empire.

^^^ i agree with the person above me, good luck on whatever : )