When Mr. Key made a chocolate milkshake for himself, he used 3/4 cup
of milk for every 3 scoops of ice cream. If his family of four all want the
same type of milkshake that he made, how many total cups of milk will use
for everybody's milkshake?

3/4 cup of milk
3 cups of milk
4 cups of milk
4/3 cups of milk