Which of the statements best describes density?
a. the mass that a mole of substance has, measured in grams per mole.
b. the amount of substance dissolved in a liquid, measured in moles per liter.
c. the mass of substance dissolved in a liquid, measured in grams per milliliter.
d. the ratio of a substance's mass to its volume, measured in grams per milliliter and also equivalent to grams per cubic centimeter.

The answer to your question is: letter D.

Explanation:

a.The mass that a mole of substance has, measured in grams per mole.  Density is not measure in moles, so this is not the correct answer.

b.The amount of substance dissolved in a liquid, measured in moles per liter.  The substance dissolved in a liquid must be measure in grams not in moles, so this answer is incorrect.

c.The mass of substance dissolved in a liquid, measured in grams per milliliter.  I think that this definition is correct but is incomple, so this answer is wrong.

d.The ratio of a substance's mass to its volume, measured in grams per milliliter and also equivalent to grams per cubic centimeter. This is the right description to density, so this is the correct answer.