Final answer:
Augustine adopted the Neoplatonic view from Plotinus that good is the ultimate reality and source of all existence, interpreting it within a Christian framework to assert that God, who is all-good, created everything as good, and that evil is a lack of good, not an independent entity.
Step-by-step explanation:
From Neoplatonism, Augustine took the idea that good is the ultimate reality and source of all existence. Influenced by the works of Plato and his followers, Augustine viewed the material world as secondary to the realm of the forms, where the ultimate truths and goods reside.
Neoplatonism, especially the works of Plotinus, emphasized 'The One' or 'The Good' as the highest principle. Augustine adapted these ideas into a Christian context, maintaining that God, as the epitome of goodness, created everything as good and that evil is not a substance but rather a privation or absence of good.
Augustine rejected the Manichean notion that there is a real force of evil equal in power to good. Instead, he asserted in his theological writings that all of creation was inherently good because God created it.
Challenges to the notion of an all-loving and all-powerful deity, such as the existence of evil, led Augustine to reconcile these by arguing that what appears to be evil in our world is, in the divine perspective, a necessary component of the universe's overall goodness.
This conception allows for the coexistence of free will and divine omniscience, as humans have the power to turn away from good, which results in sin. This view is derived from and imbued with the Platonic idea that true reality, and therefore true goodness, is beyond the physical world, and that the material world is merely a reflection of that higher reality.
The correct option is C) The ultimate reality and source of all existence.