If $\alpha$ and $\beta$ are the roots of $x^{2}+p x+q=0$ and $\alpha^{4}$ and $\beta^{4}$ are the roots of $x^{2}-r x+s=0$, then the equation $x^{2}-4 q x+2 q^{2}-r=0$ has always
(A) two real roots
(B) two positive roots
(C) two negative roots
(D) one positive and one negative root