Answer: <u>Option A, OPEC
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Explanation: Around 80 percent of oil production was accounted by OPEC in the year 2018. It is an organization of fifteen countries, which contain majority of oil reserves. Mainly the oil comes from the middle-eastern countries; namely Kuwait, Iran, Iraq, Qatar, etc.
United Nations and European Union hold very minute share in world's oil production. Exxon's share is also less than ten percent.
Bacteria, viruses, and fungi are all pathogens that are attacked by the immune system.
