Final answer:
The use of naturalistic forms supports the belief that the Christ as Good Shepherd from the Mausoleum of Galla Placidia at Ravenna is deeply rooted in the classical tradition, as it reflects the tendency of Early Christian and Byzantine art to draw upon and renew classical art models.
Step-by-step explanation:
The Christ as Good Shepherd from the Mausoleum of Galla Placidia in Ravenna is an example of art that is deeply rooted in the classical tradition. The statement that would support this belief is b) Use of naturalistic forms. This is evident when comparing it to classical art forms, such as the imagery present in Early Christian art which borrowed heavily from pagan art, and the tendency to revive styles from the classical period, such as what we see during the Carolingian and Byzantine periods.
Early Christian and Roman art like the Mausoleum of Galla Placidia's Good Shepherd mosaic blends Roman and Christian symbolism, maintaining naturalistic imagery akin to classical art traditions. Additionally, other Byzantine art shows renewed interest in classicism, referencing Late Roman artistic models. Therefore, the adoption of naturalistic forms in the Good Shepherd mosaic is what aligns it with the classical tradition.