Coal mainly contains ________.A.HydrogenB.OxygenC.CarbonD.Sodium

The correct answer is C. Carbon.

Explanation:
Coal is primarily composed of carbon, which makes up about 60-90% of its mass, depending on the type of coal. The carbon content in coal is what gives it its energy-producing capabilities when burned. Here’s a breakdown of the options:

A. Hydrogen: While coal does contain hydrogen, it is in much smaller quantities compared to carbon.

B. Oxygen: Coal does have oxygen in its structure, but like hydrogen, the amount is significantly less than carbon.

C. Carbon: This is the main element in coal. The carbon content is responsible for coal's energy density and combustibility.

D. Sodium: Sodium is not a significant component of coal.

Thus, coal is mainly composed of carbon, making option C the best answer.