The concentration of a solution would remain constant after adding solute to the solution. This is because while the amount of solute increases, the total volume of the solution also increases proportionately, depending on how much solute is added, which can keep the concentration constant if done in the right ratio.
However, it’s important to note that typically adding solute increases the concentration, but if the addition compensates for the volume change appropriately (not in a practical sense, but theoretically), it could remain constant for a specific scenario.
In general practical terms, none of the options provided lead to a scenario where the concentration would definitely remain constant under normal circumstances.