M is a set of six consecutive even integers. When the least three integers of set M are summed, the result is x. When the greatest three integers of set M are summed, the result is y. Which of the following is true?
(A) y = x − 18
(B) y = x + 18
(C) y = 2x
(D) y = 2x + 4
(E) y = 2x + 6