Manmade global warming is caused by

Human activity--such as burning fossil fuels--causes more greenhouse gases to build up in the atmosphere. As the atmosphere "thickens" with more greenhouse gases, more heat is held in. Fossil fuels such as oil, coal and natural gas are high in carbon and, when burned, produce major amounts of carbon dioxide or CO2.

Ithink your answer is d

Cin carbonh in hydrogeno in oxygen