What does % M/V (percent mass volume) indicate?

The correct answer highlights that % M/V (percent mass/volume) is a way to express concentration, specifically indicating how much mass of a solute is contained in a certain volume of solution. This means that % M/V is calculated by taking the mass of the solute in grams, dividing it by the total volume of the solution in milliliters, and then multiplying by 100 to express it as a percentage. For instance, a 5% M/V solution means there are 5 grams of solute in every 100 milliliters of solution.

This measurement is particularly useful in fields such as biochemistry and pharmacology, where precise concentrations of solutions are crucial for reactions and treatments. The other options do not accurately describe how % M/V is defined or calculated, emphasizing why this selection is the most appropriate in the context of understanding solution concentrations.