Multiply the volume in liters (4.00L) by the concentration of the solution in molar (0.250M) to calculate the number of moles of soluto that you need, then multiply the number of moles by the molar mass of sodium hydroxide (39.99 g/mol) to calculate the mass.
4.00L x 0.250 M x 39.99g / 1L = 39.99g
Basically you need one mol of NaOH (39.99g) dissolved in 4 liters of solution.
The answer is D or 4,3,2!
