Answer:
d. The idea of conflict between a god of good and a god of evil.
Step-by-step explanation:
Zoroastrianism was the religious faith/sect founded by Zoroaster, an Iranian spiritual leader. This religion concerns or revolves around the dualistic nature of the god of good and the god of bad in constant conflict against each other. This dual nature is also found in humans, s it is based off this constant battle for supremacy over an individual's nature that the religion is based off.
This monotheistic religion is also perceived to be the precursor of the many more westernized religions like Judaism, Christianity, Muslims etc, impacting their belief systems and influencing the teachings. This was between the good and bad is also evident in all religions. This religious dualism between the god of the good Ahura and the god of the bad Ahriman is the main proponent and feature of this Zoroastrian religion.