Let `alpha+ibeta;alpha,beta in R ,` be a root of the equation `x^3+q x+r=0; q ,r in Rdot` A real cubic equation, independent of `alpha&beta,` whose one root is `2alpha` is `x^3+q x-4=0` (b) `x^3-q x+4=0` `x^3+2q x+r=0` (d) None of these