Which statement correctly defines molarity and molality and their units?

Which statement correctly defines molarity and molality and their units?

• A. Molarity is grams per liter; unit g/L. Molality is grams per kilogram; unit g/kg.
• B. Molarity is moles of solute per liter of solution; unit mol/L. Molality is moles per kilogram of solvent; unit mol/kg.
• C. Molarity is moles per liter of solvent; unit mol/L. Molality is moles per liter of solution; unit mol/L.
• D. Molarity is moles per kilogram of solvent; unit mol/kg. Molality is moles per liter of solution; unit mol/L.

Answer: (B)