Which of the Following Best Explains Why Carbon Dioxide Emissions

Which of the following best explains why carbon dioxide emissions are so much higher using tar sands compared to conventional crude oil?

A) tar sands require additional energy to produce.
B) tar sands contain carbon dioxide trapped within the sand.
C) tar sands are found at higher latitude and naturally contain more carbon dioxide.
D) oxygen within tar sands readily combines with the carbon.
E) tar sands naturally contain water.