Final answer:
The correct option is (B) . A lower absorbance reading for ORO indicates a lower concentration of ORO in a solution. If solution B has a higher osmolality than solution A, it suggests that solution B has more solutes, meaning a higher concentration of osmotically active particles.
Step-by-step explanation:
A lower absorbance reading for Oil Red O (ORO), a dye used for staining fats in cells and tissues, typically indicates a lower concentration of ORO in the solution because absorbance is directly related to the concentration of the absorbing species in solution following the Beer-Lambert law. Therefore, when the absorbance reading is lower, it means that less light is being absorbed by the solution, which in turn suggests that there is a lower amount of ORO present to absorb the light.
In the context of osmolality measurements of aqueous solutions A and B, if solution B has a much higher osmolality than solution A, it indicates that solution B has a higher concentration of solutes. This is because osmolality refers to the concentration of osmotically active particles in a solution, which is expressed as the number of moles of solute per kilogram of solvent (not solute, as incorrectly stated in the provided information).