Ans: D
Since the quadratic equation has equal roots, $\Delta =0$. Hence, we have
Since the quadratic equation has equal roots, $\Delta =0$. Hence, we have
$\begin{array}{rcl}
b^2 – 4(1)(4b) & = & 0 \\
b^2 -16b & = & 0 \\
b(b – 16) & = & 0
\end{array}$
Therefore, $b=0$ or $b=16$.
