First, you convert liters to moles.
Usually you have to go to grams but this is STP.
Get moles directly by dividing the 4 by STP (22.4)

About

or 0.18 moles whichever your teacher prefers
I think it's Almond Soy Milk because they're recommending your body's pH to be at 7.5 and the Almond Soy Milk is the answer with the closest pH to 7.5