8. Which statements regarding natural gas formation and the factors in its production are correct?A. Having porous and permeable rock is the only important condition for the formation and viability of natural gas under the ground.B. The amount and value of the gas under the ground are the only important factors in the decision to drill a well to produce the gas.C. Fine reservoir rock grains with rhombohedral packing provide more porosity compared to coarse reservoir rock grains with cubic packing.D. If pore volume is equal to 109 ft3, and the total rock volume is 5109, then the porosity of the rock is 20%.