Currently,the Biggest Drawbacks to Using the New Clean Coal Technologies

Currently,the biggest drawbacks to using the new clean coal technologies are ____________________.

A) the energy required and costs involved in using them
B) the negativity of the public and their reluctance to pay more for electricity
C) the technologies do not exist and too much energy is needed to develop them
D) the fact that it has not been proven that coal is toxic and that there are no alternatives
E) government incentives and the public apathy