Primordial swamps decomposing under ancient seas and tons of rock layers gave rise to an important fuel used today. That fuel is

I believe the answer is D, though I'm not entirely certain unfortunately.

Density is calculated as mass divided by volume.
  Step one:
Convert m³ to ml.
1 m³ = 1,000,000 ml
0.250 m³ x 1,000,000 = 250,000 ml
  Step two: Convert mg to g.
1 mg = 0.001 g, hence 4.25 x 10^8 mg equals 0.459 g.
Consequently, the density comes out to be 0.459 g/250,000 = 1.836 x 10^-6 g/ml.

Answer:

Explanation:

The concept of mass balance around a distillation tower is utilized.

Each column undergoes mass and component balance, with relevant substitutions and analyses detailed in the attached documents.