Final answer:
The correct answer is C. 1.785 x 10^-4 g/mL, which properly expresses the density value in scientific notation and appropriate units of g/mL.
Step-by-step explanation:
The question is asking for the correct format of a density value in proper scientific notation. Density is the ratio of the mass of a substance to its volume. The SI unit for density is kilograms per cubic meter (kg/m³), but in many practical cases, especially for solids and liquids, it is given in grams per cubic centimeter (g/cm³) or grams per milliliter (g/mL).
Gases are usually reported in grams per liter (g/L). Considering the options provided, the proper scientific notation for a very small density value would be represented as a number between 1 and 10 multiplied by a power of 10. Therefore, the correct answer is C. 1.785 x 10^-4 g/mL, which represents the density in g/mL and appropriately expresses the number in scientific notation.