The correct answer is A. 1.0 and 0.0.
Porosity is the ratio of the volume of voids to the total volume of soil, while voids ratio is the ratio of the volume of voids to the volume of solids. If the volume of voids is equal to the volume of solids, then the porosity and voids ratio are both 1.0.
Option B is incorrect because the volume of voids cannot be greater than the total volume of soil. Option C is incorrect because the volume of voids cannot be less than the volume of solids. Option D is incorrect because the porosity and voids ratio are not equal.