B. The unknown solution had the lower concentration.
Explanation:
Osmosis is a phenomenon in which the molecules of the solvent has a tendency to move through a membrane which is semipermeable from lower concentrated side to the higher concentration side, so that the concentrations on both sides of the membrane must be equal.
So the unknown solution may have lesser concentration than the isotonic solution so that molecules of that solution move from less concentrated side to the more concentrated side, so its level drops.
<span> Cement products are essential for construction and civil engineering, while lime is irreplaceable for the steel industry, as well as construction materials, paints, plastics, and rubber.</span>
Two electrons that are of the same charge will repel each other
