a is a real number. x1 and x2 are the distinct roots of x^2 \plus{} ax \plus{} 2 \equal{} x. x3 and x4 are the distinct roots of (x \minus{} a)^2 \plus{} a(x \minus{} a) \plus{} 2 \equal{} x. If x_3 \minus{} x_1 \equal{} 3(x_4 \minus{} x_2), then x_4 \minus{} x_2 will be ?<spanclass=′latex−bold′>(A)</span>2a<spanclass=′latex−bold′>(B)</span>3a<spanclass=′latex−bold′>(C)</span>32a<spanclass=′latex−bold′>(D)</span>23a<spanclass=′latex−bold′>(E)</span>None