Ans: (A, D)
Hint : \(x^{2}-4 b x+2 b^{2}-c=0\)
let \(\alpha_{1}, \beta_{1}\) be roots
$$
\begin{aligned}
\alpha_{1}, \beta_{1} &=2 b^{2}-c \\
&=2 b^{2}-\left(a^{4}-4 a^{2} b+2 b^{2}\right) \\
&=a^{2}\left(4 b-a^{2}\right)<0
\end{aligned}
$$
Hence one positive and one negative