Final Answer:
The fourth "Doctor of the Church" is Ambrose.
Step-by-step explanation:
Augustine: Augustine, also known as Saint Augustine of Hippo, was a prominent theologian and philosopher in the Christian tradition. His influential works, such as "Confessions" and "City of God," shaped Western Christian thought.
Jerome: Saint Jerome was a Christian scholar and priest best known for translating the Bible into Latin, creating the Vulgate, which became the standard Bible in the Western Christian Church.
Gregory the Great: Pope Gregory I, also known as Gregory the Great, was a pope and theologian. He is recognized for his contributions to liturgy and music and is known for the Gregorian Chant.
Ambrose: Saint Ambrose, the Bishop of Milan, is the fourth Doctor of the Church. He played a crucial role in the conversion of Augustine and was known for his theological writings and hymns.