Final answer:
The poor thermal conductors in teeth are Dentin and Pulp due to their composition and placement within the tooth's structure.
Step-by-step explanation:
The layers of a tooth that are poor thermal conductors are Dentin and Pulp. Dentin is a bone-like tissue that forms the main bulk of the tooth, lying beneath the enamel in the crown and the cementum in the root. The innermost layer of a tooth is the pulp, which contains nerves and blood vessels and is considered to be a poor thermal conductor due to its composition. Thus, the correct answer is C. Dentin and Pulp.