Answer: A. To achieve union with God.
Explanation: Which best describes what Augustine believed to be the ultimate goal of the human life is that he thought it's to achieve union with God after you have died. And he stated in his Doctrine of Double Happiness that " This world is too plagued with unsatisfied desires to achieve that ultimate good which we all seek by nature. Furthermore, God has basically created us with a desire to come to perfect knowledge of Him, but this is hidden from us while in our mortal bodies. True knowledge of God would require being able to see him directly, but this is only possible by a completely purified soul. When this occurs, we will experience the ultimate pleasure a pure and everlasting bliss in Heaven that will be the satisfaction of every human desire and the obliteration of every sadness or worry" which is why this answer choice is correct.