Final answer:
The detail that did not derive from classical tradition but emerged in the early Christian period is the depiction of human figures in art. Early Christian art opposed monumental religious sculpture and instead focused on relief sculptures, consular diptychs, and other smaller objects that emphasized symbolism and ideas.
Step-by-step explanation:
The detail that did not derive from classical tradition but emerged in the early Christian period is b) Depiction of human figures in art.
During the classical period, statues in stone or bronze were used to depict human figures, but early Christian art opposed monumental religious sculpture and instead focused on relief sculptures and smaller objects like consular diptychs. The emphasis shifted from naturalistic illusionism to symbolism and ideas.
This change in artistic style reflected the influence of Christianity and its rejection of materiality and traditional forms of beauty in favor of simplicity and self-denial.