Diamonds are transparent and graphite is dark grey both are forms of the element carbon, a non metal. Diamonds are the hardest naturally occurring material. Graphite is a very good conductor of electricity. Both are crystalline in form. There are a great number of carbon-based compounds and many are found in living tissue. Fossilized plants can form an impure form of carbon called coal. If we heat wood in the absence of air we make another impure form of carbon called charcoal. Carbon fibres are used to manufacture things that need to be strong but light.

Question: The passage described three qualities of diamonds.
Options:
A. true, B. false, C. uncertain
Answer: "B"