These graphs show global temperatures (left) and carbon emissions (right) over time. The graph of global temperatures is based on 1951-1980 average temperatures, which was 14 degrees Celsius (57.2 degrees Fahrenheit). The data show how high or low Earth's surface temperature was above that average (14 degrees Celsius). The Global Fossils Carbon Emissions graph shows annual carbon dioxide emissions based on fuel type. Human activities such as fossil fuel combustion, cement production, and agriculture all contribute to carbon emissions. Based on the data shown, what reasonable conclusion can be drawn? A) Global temperatures tend to increase as carbon emissions increase. B) Global temperatures increase over time, regardless of human activity. C) Natural gas emissions have no effect on global temperature increases. D) The burning of coal has had the greatest effect on global temperatures.