d
Sol. Characteristic equation of matric $A$
$|A-\lambda I|=0$$\left|\begin{array}{cc}1-\lambda & 2 \\2 & -5-\lambda\end{array}\right|=0$
$\lambda^{2}+4 \lambda=1$
$A^{2}+4 A=I$
$2\,A^{2}+8 A=2 I$
Given that $\alpha A^{2}+\beta A=2\,I$
Comparing equation $(1)$ and $(2)$ we get