If the operation € is defined for all x and y by the equation x € y = 2*x*y, then 8 € (4 € 5) =
Choose the correct choice from the following answers
A) 80  B) 120  C) 160  D) 640  E) 760

Rationale: "working inside out , ( 4 € 5 ) = 2 * 4 * 5 = 40 8 € 40 = 2 * 8 * 40 = 640 hence , answer is d"
Answer: D