Final answer:
To make a 0.250 molar solution, you need to take 0.250 moles of solute and add enough solvent to make 1.00 L of solution.
Step-by-step explanation:
In order to make a 0.250 molar solution, we need to take 0.250 moles of solute and add enough solvent to reach the desired volume. So, the correct action would be option a) Taking 0.250 moles of solute and adding enough solvent to make 1.00 L of solution.