Read the following passage and answer the two items that follow. Your answers to these items should be based on the passage only.Crude mineral oil comes out of the earth as a thick brown or black liquid with a strong smell. It is a complex mixture of many different substances, each with its own individual qualities. Most of them are combinations of hydrogen and carbon in varying proportions. Such hydrocarbons are also found in other forms such as bitumen, asphalt and natural gas. Mineral oil originates from the carcasses of tiny animals and from plants that live in the sea. Over millions of years, these dead creatures form large deposits under the sea-bed; and ocean currents cover them mineral hardens, it becomes sedimentary rock and effectively shuts out the oxygen, so preventing the complete decomposition of the marine deposits underneath. The layers of sedimentary rock become thicker and heavier. Their pressure produces heat, which transforms the tiny carcasses into crude oil in a process that is still going on today.Mineral oil deposits under the sea do not get completely decomposed because they

• A. Are constantly washed by the ocean currents.
• B. Become rock and prevent oxygen from entering them.
• C. Contain a mixture of hydrogen and carbon.
• D. Are carcasses of organisms lying in saline conditions.