The first half...

If ${e_1}$ and ${e_2}$ are roots of the equation $x^{2}-ax+2=0$ , then the value of $a$ for which ${e_1}$ & ${e_2}$ are the eccentricities of two hyperbolae, can be...

A. $2 \sqrt{2}$

B. $\sqrt{8.5}$

C. $\frac{e+ \pi }{2}$

D. $\pi$