The correct answer is: C. pure form of carbon
Carbongen is a pure form of carbon. It is a black, non-metallic, and odorless solid. It is the fourth most abundant element in the universe and the second most abundant element in the Earth’s crust. Carbon is found in a variety of forms, including graphite, diamond, and charcoal. It is also the main component of coal, oil, and natural gas.
Carbon is a very versatile element and can be combined with other elements to form a wide variety of compounds. These compounds are essential for life and are used in a variety of industries.
Option A is incorrect because carbon monoxide (CO) and carbon dioxide (CO2) are gases.
Option B is incorrect because oxygen (O2) is a gas.
Option D is incorrect because unsaturated organic compounds are hydrocarbons that have double or triple bonds between carbon atoms.