The mineral source of many manufactured items is not commonly known. For example, few people are aware that pencil lead does not contain lead metal but is really made of the soft black mineral called graphite. Talcum powder is ground-up rock made from the mineral talc. And the common mineral quartz is the main ingredient in ordinary glass and is the source of silicon for computer chips. Frederick K. Lutgens, et al., Foundations of Earth Science, 6^th ed. A) Nonargument. B) Argument; conclusion: Talcum powder ... made from the mineral talc. C) Argument; conclusion: The mineral source ... is not commonly known. D) Argument; conclusion: And the common mineral quartz ... computer chips. E) Argument; conclusion: For example, few people are aware ... called graphite.

Question

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The passage presents an argument with the conclusion that the mineral source of many manufactured items is not commonly known, supported by examples of everyday items and their mineral origins.

The Mineral Source of Many Manufactured Items Is Not Commonly