In general, the supply chain starts with A. research and development. B. final customers at the retail store. C. the provider of basic raw materials. D. a distributor.

C. the provider of basic raw materials.

Explanation:

Any supply chain starts with the providers of raw materials, because by definition, all final goods need raw materials to be produced.

A manufacturing firm may provide itself the raw materials: for example, a paper-making company that also owns a lodging operation. But it is more commonly seen that manufacturing firms have their providers of raw materials, in what is known in logistics as the upstream supply chain.