A the pipeline would release 1.3 billion tons of greenhouse emissions in 50 years if it carried tar sands oil.
B the pipeline would release 1.3 billion tons of greenhouse emissions in 50 years if it carried conventional crude oil.
C the pipeline would release the same volume of greenhouse emissions in 50 years no matter what kind of oil it carried.
D greenhouse emissions would be increased in about 1.3 billion tons in 50 years if the pipeline carried tar sands oil
E greenhouse emissions would be increased in about 1.3 billion tons in 50 years if the pipeline carried conventional crude oil.