Juan is baking muffins for the school bake sale. He needs 1 1/2 cups of flour to make a batch of blueberry muffins. He needs 2 3/4 cups of flour to make a batch of banana muffins. How much flour does Juan need to make both batches of muffins?
A) 4 1/4
B) 4
C) 3 1/2
D) 3 1/4