Elena’s bread recipe calls for 2 ounces of butter for each 5 cups of flour used. She needs to make 4 times the original recipe. If 12 ounces of butter is used, then how many cups of flour are needed?  Choose the correct choice from the following
A) 1 B) 4 C) 9 D) 13 E) 20

Rationale: "solving through algebra route : 2 b + 5 f = x amount if we multiply this equation with 4 we get : 8 b + 20 f = 4 x therefore , we got 8 ounces of butter and 4 x amount of quantity when we use 20 ounces of floor . ans : e"
Answer: E