In Order to Halt Increases in the Amounts of These

In order to halt increases in the amounts of these gases in the Earth's atmosphere,global greenhouse gas emissions must be decreased by 9 billion tons.Which of these would NOT provide that much relief in global greenhouse gas emissions?

A) Cutting energy usage in the world's buildings by 20-25% below business-as-usual.
B) Having all cars get 60 mpg instead of 30 mpg
C) Replacing 700 large coal-burning power plants with nuclear,wind,or solar power
D) Capturing and sequestering carbon dioxide at 800 coal-burning power plants
E) None of the above would provide the needed 9 billion tons.