Final answer:
Spontaneous replication errors can be caused by a tautomeric shift, wobble base pairing, and slippage but not by intercalating agents, because these agents are external chemicals that disrupt replication, while spontaneous errors occur naturally without environmental exposure.
Step-by-step explanation:
Spontaneous replication errors that occur during DNA replication can be attributed to several causes, but not all of the options listed in the question are factors in spontaneous errors. A tautomeric shift (A) involves the temporary repositioning of protons in the DNA bases, leading to mismatching during DNA replication. Wobble base pairing (B) is a concept wherein there is a less stringent pairing between the DNA base and the tRNA anticodon, which could lead to incorporation of incorrect amino acids during translation, but it does not cause replication errors directly. DNA slippage (D) can cause small insertions or deletions (indels) due to the repeated sequences slipping during replication.
Intercalating agents (C), however, are chemicals that insert between base pairs in DNA and disrupt replication, but they are not considered spontaneous as they involve external chemicals. Therefore, the answer is C, intercalating agents, because spontaneous replication errors occur without any exposure to environmental agents and are a result of natural reactions taking place within the body.