What Is the Major Drawback to Using Bituminous Coal as an Energy

What is the major drawback to using bituminous coal as an energy source?

A) It has very low carbon content.
B) It contains a high amount of sulfur, which when burned contributes to acid rain.
C) It has an extremely high surface area, which makes it difficult to burn.
D) Bituminous coal is noncrystalline, which gives it a low energy/gram ratio.
E) Bituminous coal is very expensive to produce and transport.