48*1=48.
First of all, Mark used 48 cups of orange juice.
But wait. That isn't an answer choice!
Well then, it problably can be simplified to other units.
Since all the answer choices are in quarts, you can see that you should probably simplify it to quarts.
Since there are 4 cups in each quart, 48 cups is equal to 48/4=12 quarts.
Mark used B)12 quarts of orange juice.
Hope this helps!